A Triangulation Checklist Born From the Question; “Why NOT Use Close Relatives for Triangulation?”

One of my readers asked why we don’t use close relatives for triangulation.

This is a great question because not using close relatives for triangulation seems counter-intuitive.

I used to ask my kids and eventually my students and customers if they wanted the quick short answer or the longer educational answer.

The short answer is “because close relatives are too close to reliably form the third leg of the triangle.” Since you share so much DNA with close relatives, someone matching you who is identical by chance can also match them for exactly the same reason.

If you trust me and you’re good with that answer, wonderful. But I hope you’ll keep reading because there’s so much to consider, not to mention a few gotchas. I’ll share my methodology, techniques, and workarounds.

We’ll also discuss absolutely wonderful ways to utilize close relatives in the genetic genealogical process – just not for triangulation.

At the end of this article, I’ve provided a working triangulation checklist for you to use when evaluating your matches.

Let’s go!

The Step-by-Step Educational Answer😊

Some people see “evidence” they believe conflicts with the concept that you should not use close relatives for triangulation. I understand that, because I’ve gone down that rathole too, so I’m providing the “educational answer” that explains exactly WHY you should not use close relatives for triangulation – and what you should do.

Of course, we need to answer the question, “Who actually are close relatives?”

I’ll explain the best ways to best utilize close relatives in genetic genealogy, and why some matches are deceptive.

You’ll need to understand the underpinnings of DNA inheritance and also of how the different vendors handle DNA matching behind the scenes.

The purpose of autosomal DNA triangulation is to confirm that a segment is passed down from a particular ancestor to you and a specific set of your matches.

Triangulation, of course, implies 3, so at least three people must all match each other on a reasonably sized portion of the same DNA segment for triangulation to occur.

Matching just one person only provides you with one path to that common ancestor. It’s possible that you match that person due to a different ancestor that you aren’t aware of, or due to chance recombination of DNA.

It’s possible that your or your match inherited part of that DNA from your maternal side and part from your paternal side, meaning that you are matching that other person’s DNA by chance.

I wrote about identical by descent (IBD), which is an accurate genealogically meaningful match, and identical by chance (IBC) which is a false match, in the article Concepts – Identical by…Descent, State, Population and Chance.

I really want you to understand why close relatives really shouldn’t be used for triangulation, and HOW close relative matches should be used, so we’re going to discuss all of the factors that affect and influence this topic – both the obvious and little-understood.

  • Legitimate Matches
  • Inheritance and Triangulation
  • Parental Cross-Matching
  • Parental Phasing
  • Automatic Phasing at FamilyTreeDNA
  • Parental Phasing Caveats
  • Pedigree Collapse
  • Endogamy
  • How Many Identical-by-Chance Matches Will I Have?
  • DNA Doesn’t Skip Generations (Seriously, It Doesn’t)
  • Your Parents Have DNA That You Don’t (And How to Use It)
  • No DNA Match Doesn’t Mean You’re Not Related
  • Imputation
  • Ancestry Issues and Workarounds
  • Testing Close Relatives is VERY Useful – Just Not for Triangulation
  • Triangulated Matches
  • Building Triangulation Evidence – Ingredients and a Recipe
  • Aunts/Uncles
  • Siblings
  • How False Positives Work and How to Avoid Them
  • Distant Cousins Are Best for Triangulation & Here’s Why
  • Where Are We? A Triangulation Checklist for You!
  • The Bottom Line

Don’t worry, these sections are logical and concise. I considered making this into multiple articles, but I really want it in one place for you. I’ve created lots of graphics with examples to help out.

Let’s start by dispelling a myth.

DNA Doesn’t Skip Generations!

Recently, someone emailed to let me know that they had “stopped listening to me” in a presentation when I said that if a match did not also match one of your parents, it was a false match. That person informed me that they had worked on their tree for three years at Ancestry and they have “proof” of DNA skipping generations.

Nope, sorry. That really doesn’t happen, but there are circumstances when a person who doesn’t understand either how DNA works, or how the vendor they are using presents DNA results could misunderstand or misinterpret the results.

You can watch my presentation, RootsTech session, DNA Triangulation: What, Why and How, for free here. I’m thrilled that this session is now being used in courses at two different universities.

DNA really doesn’t skip generations. You CANNOT inherit DNA that your parents didn’t have.

Full stop.

Your children cannot inherit DNA from you that you don’t carry. If you don’t have that DNA, your children and their descendants can’t have it either, at least not from you. They of course do inherit DNA from their other parent.

I think historically, the “skipping generations” commentary was connected to traits. For example, Susie has dimples (or whatever) and so did her maternal grandmother, but her mother did not, so Susie’s dimples were said to have “skipped a generation.” Of course, we don’t know anything about Susie’s other grandparents, if Susie’s parents share ancestors, recessive/dominant genes or even how many genetic locations are involved with the inheritance of “dimples,” but I digress.

DNA skipping generations is a fallacy.

You cannot legitimately match someone that your parent does not, at least not through that parent’s side of the tree.

But here’s the caveat. You can’t match someone one of your parents doesn’t with the rare exception of:

  • Relatively recent pedigree collapse that occurs when you have the same ancestors on both sides of your tree, meaning your parents are related, AND
  • The process of recombination just happened to split and recombine a segment of DNA in segments too small for your match to match your parents individually, but large enough when recombined to match you.

We’ll talk about that more in a minute.

However, the person working with Ancestry trees can’t make this determination because Ancestry doesn’t provide segment information. Ancestry also handles DNA differently than other vendors, which we’ll also discuss shortly.

We’ll review all of this, but let’s start at the beginning and explain how to determine if our matches are legitimate, or not.

Legitimate Matches

Legitimate matches occur when the DNA of your ancestor is passed from that ancestor to their descendants, and eventually to you and a match in an unbroken pathway.

Unbroken means that every ancestor between you and that ancestor carried and then passed on the segment of the ancestor’s DNA that you carry today. The same is true for your match who carries the same segment of DNA from your common ancestor.

False positive matches occur when the DNA of a male and female combine randomly to look like a legitimate match to someone else.

Thankfully, there are ways to tell the difference.

Inheritance and Triangulation

Remember, you inherit two copies of each of your chromosomes 1-22, one copy from your mother and one from your father. You inherit half of the DNA that each parent carries, but it’s mixed together in you so the labs can’t readily tell which nucleotide, A, C, T, or G you received from which parent. I’m showing your maternal and paternal DNA in the graphic below, stacked neatly together in a column – but in reality, it could be AC in one position and CA in the next.

For matching all that matters is the nucleotide that matches your match is present in one of those two locations. In this case, A for your mother’s side and C for your father’s side. If you’re interested, you can read more about that in the article, Hit a Genealogy Home Run Using Your Double-Sided Two-Faced Chromosomes While Avoiding Imposters.

You can see in this example that you inherited all As from your Mom and all Cs from your Dad.

  • A legitimate maternal match would match you on all As on this particular example segment.
  • A legitimate paternal match would match you on all Cs on this particular segment.
  • A false positive match will match you on some random combination of As and Cs that make it look like they match you legitimately, but they don’t.
  • A false positive match will NOT match either your mother or your father.

To be very clear, technically a false positive match DOES match your DNA – but they don’t match your DNA because you share a common ancestor with your match. They match you because random recombination on their side causes you to match each other by chance.

In other words, if part of your DNA came from your Mom’s side and part from your Dad’s but it randomly fell in the correct positional order, you’d still match someone whose DNA was from only their mother or father’s side. That’s exactly the situation shown above and below.

Looking at our example again, it’s evident that your identical by chance (IBC) match’s A locations (1, 3, 5, 7 & 9) will match your Mom. C locations (2, 4, 6 8, & 10) will match your Dad, but the nonmatching segments interleaved in-between that match alternating parents will prevent your match from matching either of your parents. In other words, out of 10 contiguous locations in our example, your IBC match has 5 As alternated with 5 Cs, so they won’t match either of your parents who have 10 As or 10 Cs in a row.

This recombination effect can work in either direction. Either or both matching people’s DNA could be randomly mixed causing them to match each other, but not their parents.

Regardless of whose DNA is zigzagging back and forth between maternal and paternal, the match is not genealogical and does not confirm a common ancestor.

This is exactly why triangulation works and is crucial.

If you legitimately match a third person, shown below, on your maternal side, they will match you, your first legitimate maternal match, and your Mom because they carry all As. But they WON’T match the person who is matching you because they are identical by chance, shown in grey below.

The only person your identical by chance match matches in this group is you because they match you because of the chance recombination of parental DNA.

That third person WILL also match all other legitimate maternal matches on this segment.

In the graphic above, we see that while the grey identical by chance person matches you because of the random combination of As from your mother and Cs from your father, your legitimate maternal matches won’t match your identical by chance match.

This is the first step in identifying false matches.

Parental Cross-Matching

Removing the identical by chance match, and adding in the parents of your legitimate maternal match, we see that your maternal match, above, matches you because you both have all As inherited from one parent, not from a combination of both parents.

We know that because we can see the DNA of both parents of both matches in this example.

The ideal situation occurs when two people match and they have both had their parents tested. We need to see if each person matches the other person’s parents.

We can see that you do NOT match your match’s father and your match does NOT match your father.

You do match your match’s mother and your match does match your mother. I refer to this as Parental Cross-matching.

Your legitimate maternal matches will also match each other and your mother if she is available for testing.

All the people in yellow match each other, while the two parents in gray do not match any of your matches. An entire group of legitimate maternal matches on this segment, no matter how many, will all match each other.

If another person matches you and the other yellow people, you’ll still need to see if you match their parents, because if not, that means they are matching you on all As because their two parents DNA combined just happened, by chance, to contribute an A in all of those positions.

In this last example, your new match, in green, matches you, your legitimate match and both of your mothers, BUT, none of the four yellow people match either of the new match’s parents. You can see that the new green match inherited their As from the DNA of their mother and father both, randomly zigzagging back and forth.

The four yellow matches phase parentally as we just proved with cross matching to parents. The new match at first glance appears to be a legitimate match because they match all of the yellow people – but they aren’t because the yellow people don’t match the green person’s parents.

To tell the difference between legitimate matches and identical by chance matches, you need two things, in order.

  • Parental matching known as parental phasing along with parental cross-matching, if possible, AND
  • Legitimate identical by descent (IBD) triangulated matches

If you have the ability to perform parental matching, called phasing, that’s the easiest first step in eliminating identical by chance matches. However, few match pairs will have parents for everyone. You can use triangulation without parental phasing if parents aren’t available.

Let’s talk about both, including when and how close relatives can and cannot be used.

Parental Phasing

The technique of confirming your match to be legitimate by your match also matching one of your parents is called parental phasing.

If we have the parents of both people in a match pair available for matching, we can easily tell if the match does NOT match either parent. That’s Parental Cross Matching. If either match does NOT match one of the other person’s parents, the match is identical by chance, also known as a false positive.

See how easy that was!

If you, for example, is the only person in your match pair to have parents available, then you can parentally phase the match on your side if your match matches your parents. However, because your match’s parents are unavailable, your match to them cannon tbe verified as legitimate on their side. So you are not phased to their parents.

If you only have one of your parents available for matching, and your match does not match that parent, you CANNOT presume that because your match does NOT match that parent, the match is a legitimate match for the other, missing, parent.

There are four possible match conditions:

  • Maternal match
  • Paternal match
  • Matches neither parent which means the match is identical by chance meaning a false positive
  • Matches both parents in the case of pedigree collapse or endogamy

If two matching people do match one parent of both matches (parental cross-matching), then the match is legitimate. In other words, if we match, I need to match one of your parents and you need to match one of mine.

It’s important to compare your matches’ DNA to generationally older direct family members such as parents or grandparents, if that’s possible. If your grandparents are available, it’s possible to phase your matches back another generation.

Automatic Phasing at FamilyTreeDNA

FamilyTreeDNA automatically phases your matches to your parents if you test that parent, create or upload a GEDCOM file, and link your test and theirs to your tree in the proper places.

FamilyTreeDNA‘s Family Matching assigns or “buckets” your matches maternally and paternally. Matches are assigned as maternal or paternal matches if one or both parents have tested.

Additionally, FamilyTreeDNA uses triangulated matches from other linked relatives within your tree even if your parents have not tested. If you don’t have your parents, the more people you identify and link to your tree in the proper place, the more people will be assigned to maternal and paternal buckets. FamilyTreeDNA is the only vendor that does this. I wrote about this process in the article, Triangulation in Action at Family Tree DNA.

Parental Phasing Caveats

There are very rare instances where parental phasing may be technically accurate, but not genealogically relevant. By this, I mean that a parent may actually match one of your matches due to endogamy or a population level match, even if it’s considered a false positive because it’s not relevant in a genealogical timeframe.

Conversely, a parent may not match when the segment is actually legitimate, but it’s quite rare and only when pedigree collapse has occurred in a very specific set of circumstances where both parents share a common ancestor.

Let’s take a look at that.

Pedigree Collapse

It’s not terribly uncommon in the not-too-distant past to find first cousins marrying each other, especially in rather closely-knit religious communities. I encounter this in Brethren, Mennonite and Amish families often where the community was small and out-marrying was frowned upon and highly discouraged. These families and sometimes entire church congregations migrated cross-country together for generations.

When pedigree collapse is present, meaning the mother and father share a common ancestor not far in the past, it is possible to inherit half of one segment from Mom and the other half from Dad where those halves originated with the same ancestral couple.

For example, let’s say the matching segment between you and your match is 12 cM in length, shown below. You inherited the blue segment from your Dad and the neighboring peach segment from Mom – shown just below the segment numbers. You received 6 cM from both parents.

Another person’s DNA does match you, shown in the bottom row, but they are not shown on the DNA match list of either of your parents. That’s because the DNA segments of the parents just happened to recombine in 6 cM pieces, respectively, which is below the 7 cM matching threshold of the vendor in this example.

If the person matched you at 12 cM where you inherited 8 cM from one parent and 4 from the other, that person would show on one parent’s match list, but not the other. They would not be on the parent’s match list who contributed only 4 cM simply because the DNA divided and recombined in that manner. They would match you on a longer segment than they match your parent at 8 cM which you might notice as “odd.”

Let’s look at another example.

click to enlarge image

If the matching segment is 20 cM, the person will match you and both of your parents on different pieces of the same segment, given that both segments are above 7 cM. In this case, your match who matches you at 20 cM will match each of your parents at 10 cM.

You would be able to tell that the end location of Dad’s segment is the same as the start location of Mom’s segment.

This is NOT common and is NOT the “go to” answer when you think someone “should” match your parent and does not. It may be worth considering in known pedigree collapse situations.

You can see why someone observing this phenomenon could “presume” that DNA skipped a generation because the person matches you on segments where they don’t match your parent. But DNA didn’t skip anything at all. This circumstance was caused by a combination of pedigree collapse, random division of DNA, then random recombination in the same location where that same DNA segment was divided earlier. Clearly, this sequence of events is not something that happens often.

If you’ve uploaded your DNA to GEDmatch, you can select the “Are your parents related?” function which scans your DNA file for runs of homozygosity (ROH) where your DNA is exactly the same in both parental locations for a significant distance. This suggests that because you inherited the exact same sequence from both parents, that your parents share an ancestor.

If your parents didn’t inherit the same segment of DNA from both parents, or the segment is too short, then they won’t show as “being related,” even if they do share a common ancestor.

Now, let’s look at the opposite situation. Parental phasing and ROH sometimes do occur when common ancestors are far back in time and the match is not genealogically relevant.

Endogamy

I often see non-genealogical matching occur when dealing with endogamy. Endogamy occurs when an entire population has been isolated genetically for a long time. In this circumstance, a substantial part of the population shares common DNA segments because there were few original population founders. Much of the present-day population carries that same DNA. Many people within that population would match on that segment. Think about the Jewish community and indigenous Americans.

Consider our original example, but this time where much of the endogamous population carries all As in these positions because one of the original founders carried that nucleotide sequence. Many people would match lots of other people regardless of whether they are a close relative or share a distant ancestor.

People with endogamous lines do share relatives, but that matching DNA segment originated in ancestors much further back in time. When dealing with endogamy, I use parental phasing as a first step, if possible, then focus on larger matches, generally 20 cM or greater. Smaller matches either aren’t relevant or you often can’t tell if/how they are.

At FamilyTreeDNA, people with endogamy will find many people bucketed on the “Both” tab meaning they triangulate with people linked on both sides of the tester’s tree.

An example of a Jewish person’s bucketed matches based on triangulation with relatives linked in their tree is shown above.

Your siblings, their children, and your children will be related on both your mother’s and father’s sides, but other people typically won’t be unless you have experienced either pedigree collapse where you are related both maternally and paternally through the same ancestors or you descend from an endogamous population.

How Many Identical-by-Chance Matches Will I Have?

If you have both parents available to test, and you’re not dealing with either pedigree collapse or endogamy, you’ll likely find that about 15-20% of your matches don’t match your parents on the same segment and are identical by chance.

With endogamy, you’ll have MANY more matches on your endogamous lines and you’ll have some irrelevant matches, often referred to as “false positive” matches even though they technically aren’t, even using parental phasing.

Your Parents Have DNA That You Don’t

Sometimes people are confused when reviewing their matches and their parent’s match to the same person, especially when they match someone and their parent matches them on a different or an additional segment.

If you match someone on a specific segment and your parents do not, that’s a false positive FOR THAT SEGMENT. Every segment has its own individual history and should be evaluated individually. You can match someone on two segments, one from each parent. Or three segments, one from each parent and one that’s identical by chance. Don’t assume.

Often, your match will match both you and your parent on the same segment – which is a legitimate parentally phased match.

But what if your match matches your parent on a different segment where they don’t match you? That’s a false positive match for you.

Keep in mind that it is possible for one of your matches to match your parent on a separate or an additional segment that IS legitimate. You simply didn’t inherit that particular segment from your parent.

That’s NOT the same situation as someone matching you that does NOT match one of your parents on the same segment – which is an identical by chance or false match.

Your parent having a match that does not match you is the reverse situation.

I have several situations where I match someone on one segment, and they match my parent on the same segment. Additionally, that person matches my parent on another segment that I did NOT inherit from that parent. That’s perfectly normal.

Remember, you only inherit half of your parent’s DNA, so you literally did NOT inherit the other half of their DNA. Your mother, for example, should have twice as many matches as you on her side because roughly half of her matches won’t match you.

That’s exactly why testing your parents and close family members is so critical. Their matches are as valid and relevant to your genealogy as your own. The same is true for other relatives, such as aunts and uncles with whom you share ALL of the same ancestors.

You need to work with your family member’s matches that you don’t share.

No DNA Match Doesn’t Mean You’re Not Related

Some people think that not matching someone on a DNA test is equivalent to saying they aren’t related. Not sharing DNA doesn’t mean you’re not related.

People are often disappointed when they don’t match someone they think they should and interpret that to mean that the testing company is telling them they “aren’t related.” They are upset and take issue with this characterization. But that’s not what it means.

Let’s analyze this a bit further.

First, not sharing DNA with a second cousin once removed (2C1R) or more distant does NOT mean you’re NOT related to that person. It simply means you don’t share any measurable DNA ABOVE THE VENDOR THRESHOLD.

All known second cousins match, but about 10% of third cousins don’t match, and so forth on up the line with each generation further back in time having fewer cousins that match each other.

If you have tested close relatives, check to see if that cousin matches your relatives.

Second, it’s possible to match through the “other” or unexpected parent. I certainly didn’t think this would be the case in my family, because my father is from Appalachia and my mother’s family is primarily from the Netherlands, Germany, Canada, and New England. But I was wrong.

All it took was one German son that settled in Appalachia, and voila, a match through my mother that I surely thought should have been through my father’s side. I have my mother’s DNA and sure enough, my match that I thought should be on my father’s side matches Mom on the same segment where they match me, along with several triangulated matches. Further research confirmed why.

I’ve also encountered situations where I legitimately match someone on both my mother’s and father’s side, on different segments.

Third, imputation can be important for people who don’t match and think they should. Imputation can also cause matching segment length to be overreported.

Ok, so what’s imputation and why do I care?

Imputation

Every DNA vendor today has to use some type of imputation.

Let me explain, in general, what imputation is and why vendors use it.

Over the years, DNA processing vendors who sell DNA chips to testing companies have changed their DNA chips pretty substantially. While genealogical autosomal tests test about 700,000 DNA locations, plus or minus, those locations have changed over time. Today, some of these chips only have 100,000 or so chip locations in common with chips either currently or previously utilized by other vendors.

The vendors who do NOT accept uploads, such as 23andMe or Ancestry, have to develop methods to make their newest customers on their DNA processing vendor’s latest chip compatible with their first customer who was tested on their oldest chip – and all iterations in-between.

Vendors who do accept transfers/uploads from other vendors have to equalize any number of vendors’ chips when their customers upload those files.

Imputation is the scientific way to achieve this cross-platform functionality and has been widely used in the industry since 2017.

Imputation, in essence, fills in the blanks between tested locations with the “most likely” DNA found in the human population based on what’s surrounding the blank location.

Think of the word C_T. There are a limited number of letters and words that are candidates for C_T. If you use the word in a sentence, your odds of accuracy increase dramatically. Think of a genetic string of nucleotides as a sentence.

Imputation can be incorrect and can cause both false positive and false negative matches.

For the most part, imputation does not affect close family matches as much as more distant matches. In other words, imputation is NOT going to cause close family members not to match.

Imputation may cause more distant family members not to match, or to have a false positive match when imputation is incorrect.

Imputation is actually MUCH less problematic than I initially expected.

The most likely effect of imputation is to cause a match to be just above or below the vendor threshold.

How can we minimize the effects of imputation?

  • Generally, the best result will be achieved if both people test at the same vendor where their DNA is processed on the same chip and less imputation is required.
  • Upload the results of both people to both MyHeritage and FamilyTreeDNA. If your match results are generally consistent at those vendors, imputation is not a factor.
  • GEDmatch does not use imputation but attempts to overcome files with low overlapping regions by allowing larger mismatch areas. I find their matches to be less accurate than at the various vendors.

Additionally, Ancestry has a few complicating factors.

Ancestry Issues

AncestryDNA is different in three ways.

  • Ancestry doesn’t provide segment information so it’s impossible to triangulate or identify the segment or chromosome where people match. There is no chromosome browser or triangulation tool.
  • Ancestry down-weights and removes some segments in areas where they feel that people are “too matchy.” You can read Ancestry’s white papers here and here.

These “personal pileup regions,” as they are known, can be important genealogically. In my case, these are my mother’s Acadian ancestors. Yes, this is an endogamous population and also suffers from pedigree collapse, but since this is only one of my mother’s great-grandparents, this match information is useful and should not be removed.

  • Ancestry doesn’t show matches in common if the shared segments are less than 20cM. Therefore, you may not see someone on a shared match list with a relative when they actually are a shared match.

If two people both match a third person on less than a 20 cM segment at Ancestry, the third person won’t appear on the other person’s shared match list. So, if I match John Doe on 19 cM of DNA, and I looked at the shared matches with my Dad, John Doe does NOT appear on the shared match list of me and my Dad – even though he is a match to both of us at 19 cM.

The only way to determine if John Doe is a shared match is to check my Dad’s and my match list individually, which means Dad and I will need to individually search for John Doe.

Caveat here – Ancestry’s search sometimes does not work correctly.

Might someone who doesn’t understand that the shared match list doesn’t show everyone who shares DNA with both people presume that the ancestral DNA of that ancestor “skipped a generation” because John Doe matches me with a known ancestor, and not Dad on our shared match list? I mean, wouldn’t you think that a shared match would be shown on a tab labeled “Shared Matches,” especially since there is no disclaimer?

Yes, people can be forgiven for believing that somehow DNA “skipped” a generation in this circumstance, especially if they are relatively inexperienced and they don’t understand Ancestry’s anomalies or know that they need to or how to search for matches individually.

Even if John Doe does match me and Dad both, we still need to confirm that it’s on the same segment AND it’s a legitimate match, not IBC. You can’t perform either of these functions at Ancestry, but you can elsewhere.

Ancestry WorkArounds

To obtain this functionality, people can upload their DNA files for free to both FamilyTreeDNA and MyHeritage, companies that do provide full shared DNA reporting (in common with) lists of ALL matches and do provide segment information with chromosome browsers. Furthermore, both provide triangulation in different ways.

Matching is free, but an inexpensive unlock is required at both vendors to access advanced tools such as Family Matching (bucketing) and triangulation at Family Tree DNA and phasing/triangulation at MyHeritage.

I wrote about Triangulation in Action at FamilyTreeDNA, here.

MyHeritage actually brackets triangulated segments for customers on their chromosome browser, including parents, so you get triangulation and parental phasing at the same time if you and your parent have both tested or uploaded your DNA file to MyHeritage. You can upload, for free, here.

In this example, my mother is matching to me in red on the entire length of chromosome 18, of course, and three other maternal cousins triangulate with me and mother inside the bracketed portion of chromosome 18. Please note that if any one of the people included in the chromosome browser comparison do not triangulate, no bracket is drawn around any others who do triangulate. It’s all or nothing. I remove people one by one to see if people triangulate – or build one by one with my mother included.

I wrote about Triangulation in Action at MyHeritage, here.

People can also upload to GEDmatch, a third-party site. While GEDmatch is less reliable for matching, you can adjust your search thresholds which you cannot do at other vendors. I don’t recommend routinely working below 7 cM. I occasionally use GEDmatch to see if a pedigree collapse segment has recombined below another vendor’s segment matching threshold.

Do NOT check the box to prevent hard breaks when selecting the One-to-One comparison. Checking that box allows GEDmatch to combine smaller matching segments into mega-segments for matching.

I wrote about Triangulation in Action at GEDmatch, here.

Transferring/Uploading Your DNA 

If you want to transfer your DNA to one of these vendors, you must download the DNA file from one vendor and upload it to another. That process does NOT remove your DNA file from the vendor where you tested, unless you select that option entirely separately.

I wrote full step-by-step transfer/upload instructions for each vendor, here.

Testing Close Relatives Is VERY Useful – Just Not for Triangulation

Of course, your best bet if you don’t have your parents available to test is to test as many of your grandparents, great-aunts/uncles, aunts, and uncles as possible. Test your siblings as well, because they will have inherited some of the same and some different segments of DNA from your parents – which means they carry different pieces of your ancestors’ DNA.

Just because close relatives don’t make good triangulation candidates doesn’t mean they aren’t valuable. Close relatives are golden because when they DO share a match with you, you know where to start looking for a common ancestor, even if your relative matches that person on a different segment than you do.

Close relatives are also important because they will share pieces of your common ancestor’s DNA that you don’t. Their matches can unlock the answers to your genealogy questions.

Ok, back to triangulation.

Triangulated Matches

A triangulated match is, of course, when three people all descended from a common ancestor and match each other on the same segment of DNA.

That means all three people’s DNA matches each other on that same segment, confirming that the match is not by chance, and that segment did descend from a common ancestor or ancestral couple.

But, is this always true? You’re going to hate this answer…

“It depends.”

You knew that was coming, didn’t you! 😊

It depends on the circumstances and relationships of the three people involved.

  • One of those three people can match the other two by chance, not by descent, especially if two of those people are close relatives to each other.
  • Identical by chance means that one of you didn’t inherit that DNA from one single parent. That zigzag phenomenon.
  • Furthermore, triangulated DNA is only valid as far back as the closest common ancestor of any two of the three people.

Let’s explore some examples.

Building Triangulation Evidence – Ingredients and a Recipe

The strongest case of triangulation is when:

  • You and at least two additional cousins match on the same segment AND
  • Descend through different children of the common ancestral couple

Let’s look at a valid triangulated match.

In this first example, the magenta segment of DNA is at least partially shared by four of the six cousins and triangulates to their common great-grandfather. Let’s say that these cousins then match with two other people descended from different children of their great-great-great-grandparents on this same segment. Then the entire triangulation group will have confirmed that segment’s origin and push the descent of that segment back another two generations.

These people all coalesce into one line with their common great-grandparents.

I’m only showing 3 generations in this triangulated match, but the concept is the same no matter how many generations you reach back in time. Although, over time, segments inherited from any specific ancestor become smaller and smaller until they are no longer passed to the next generation.

In this pedigree chart, we’re only tracking the magenta DNA which is passed generation to generation in descendants.

Eventually, of course, those segments become smaller and indistinguishable as they either aren’t passed on at all or drop below vendor matching thresholds.

This chart shows the average amount of DNA you would carry from each generational ancestor. You inherit half of each parent’s DNA, but back further than that, you don’t receive exactly half of any ancestor’s DNA in any generation. Larger segments are generally cut in two and passed on partially, but smaller segments are often either passed on whole or not at all.

On average, you’ll carry 7 cM of your eight-times-great-grandparents. In reality, you may carry more or you may not carry any – and you are unlikely to carry the same segment as any random other descendants but we know it happens and you’ll find them if enough (or the right) descendants test.

Putting this another way, if you divide all of your approximate 7000 cM of DNA into 7 cM segments of equal length – you’ll have 1000 7 cM segments. So will every other descendant of your eight-times-great-grandparent. You can see how small the chances are of you both inheriting that same exact 7 cM segment through ten inheritance/transmission events, each. Yet it does happen.

I have several triangulated matches with descendants of Charles Dodson and his wife, Anne through multiple of their 9 (or so) children, ten generations back in my tree. Those triangulated matches range from 7-38 cM. It’s possible that those three largest matches at 38 cM could be related through multiple ancestors because we all have holes in our trees – including Anne’s surname.

Click to enlarge image

It helps immensely that Charles Dodson had several children who were quite prolific as well.

Of course, the further back in time, the more “proof” is necessary to eliminate other unknown common ancestors. This is exactly why matching through different children is important for triangulation and ancestor confirmation.

The method we use to confirm the common ancestor is that all of the descendants who match the tester on the same segment all also match each other. This greatly reduces the chances that these people are matching by chance. The more people in the triangulation group, the stronger the evidence. Of course, parental phasing or cross-matching, where available is an added confirmation bonus.

In our magenta inheritance example, we saw that three of the males and one of the females from three different descendants of the great-grandparents all carry at least a portion of that magenta segment of great-grandpa’s DNA.

Now, let’s take a look at a different scenario.

Why can’t siblings or close relatives be used as two of the three people needed for triangulation?

Aunts and Uncles

We know that the best way to determine if a match is valid is by parental phasing – your match also matching to one of your parents.

If both parents aren’t available, looking for close family matches in common with your match is the next hint that genealogists seek.

Let’s say that you and your match both match your aunt or uncle in common or their children.

You and your aunts or uncles matching DNA only pushes your common ancestor back to your grandparents.

At that point, your match is in essence matching to a segment that belongs to your grandparents. Your matches’ DNA, or your grandparents’ DNA could have randomly recombined and you and your aunt/cousins could be matching that third person by chance.

Ok, then, what about siblings?

Siblings

The most recent common ancestor (MRCA) of you and someone who also matches your sibling is your parents. Therefore, you and your sibling actually only count as one “person” in this scenario. In essence, it’s the DNA of your parent(s) that is matching that third person, so it’s not true triangulation. It’s the same situation as above with aunts/uncles, except the common ancestor is closer than your grandparents.

The DNA of your parents could have recombined in both siblings to look like a match to your match’s family. Or vice versa. Remember Parental Cross-Matching.

If you and a sibling inherited EXACTLY the same segment of your Mom’s and Dad’s DNA, and you match someone by chance – that person will match your sibling by chance as well.

In this example, you can see that both siblings 1 and 2 inherited the exact same segments of DNA at the same locations from both of their parents.

Of course, they also inherited segments at different locations that we’re not looking at that won’t match exactly between siblings, unless they are identical twins. But in this case, the inherited segments of both siblings will match someone whose DNA randomly combined with green or magenta dots in these positions to match a cross-section of both parents.

How False Positives Work and How to Avoid Them

We saw in our first example, displayed again above, what a valid triangulated match looks like. Now let’s expand this view and take a look more specifically at how false positive matches occur.

On the left-hand (blue) side of this graphic, we see four siblings that descend through their father from Great-grandpa who contributed that large magenta segment of DNA. That segment becomes reduced in descendants in subsequent generations.

In downstream generations, we can see gold, white and green segments being added to the DNA inherited by the four children from their ancestor’s spouses. Dad’s DNA is shown on the left side of each child, and Mom’s on the right.

  • Blue Children 1 and 2 inherited the same segments of DNA from Mom and Dad. Magenta from Dad and green from Mom.
  • Blue Child 3 inherited two magenta segments from Dad in positions 1 and 2 and one gold segment from Dad in position 3. They inherited all white segments from Mom.
  • Blue Child 4 inherited all gold segments from Dad and all white segments from Mom.

The family on the blue left-hand side is NOT related to the pink family shown at right. That’s important to remember.

I’ve intentionally constructed this graphic so that you can see several identical by chance (IBC) matches.

Child 5, the first pink sibling carries a white segment in position 1 from Dad and gold segments in positions 2 and 3 from Dad. From Mom, they inherited a green segment in position 1, magenta in position 2 and green in position 3.

IBC Match 1 – Looking at the blue siblings, we see that based on the DNA inherited from Pink Child 5’s parents, Pink Child 5 matches Blue Child 4 with white, gold and gold in positions 1-3, even though they weren’t inherited from the same parent in Blue Child 4. I circled this match in blue.

IBC Match 2 – Pink Child 5 also matches Blue Children 1 and 2 (red circles) because Pink Child 5 has green, magenta, and green in positions 1-3 and so do Blue Children 1 and 2. However, Blue Children 1 and 2 inherited the green and magenta segments from Mom and Dad respectively, not just from one parent.

Pink Child 5 matches Blue Children 1, 2 and 4, but not because they match by descent, but because their DNA zigzags back and forth between the blue children’s DNA contributed by both parents.

Therefore, while Pink Child 5 matches three of the Blue Children, they do not match either parent of the Blue Children.

IBC Match 3 – Pink Child 6 matches Blue Child 3 with white, magenta and gold in positions 1-3 based on the same colors of dots in those same positions found in Blue Child 3 – but inherited both paternally and maternally.

You can see that if we had the four parents available to test, that none of the Pink Children would match either the Blue Children’s mother or father and none of the Blue Children would match either of the Pink Children’s mother or father.

This is why we can’t use either siblings or close family relatives for triangulation.

Distant Cousins Are Best for Triangulation & Here’s Why

When triangulating with 3 people, the most recent common ancestor (MRCA) intersection of the closest two people is the place at which triangulation turns into only two lines being compared and ceases being triangulation. Triangle means 3.

If siblings are 2 of the 3 matching people, then their parents are essentially being compared to the third person.

If you, your aunt/uncle, and a third person match, your grandparents are the place in your tree where three lines converge into two.

The same holds true if you’re matching against a sibling pair on your match’s side, or a match and their aunt/uncle, etc.

The further back in your tree you can push that MRCA intersection, the more your triangulated match provides confirming evidence of a common ancestor and that the match is valid and not caused by random recombination.

That’s exactly what the descendants of Charles Dodson have been able to do through triangulation with multiple descendants from several of his children.

It’s also worth mentioning at this point that the reason autosomal DNA testing uses hundreds/thousands of base pairs in a comparison window and not 3 or 6 dots like in my example is that the probability of longer segments of DNA simply randomly matching by chance is reduced with length and SNP density which is the number of SNP locations tested within that cM range.

Hence a 7 cM/500 SNP minimum is the combined rule of thumb. At that level, roughly half of your matches will be valid and half will be identical by chance unless you’re dealing with endogamy. Then, raise your threshold accordingly.

Ok, So Where are We? A Triangulation Checklist for You!

I know this has been a relatively long educational article, but it’s important to really understand that testing close relatives is VERY important, but also why we can’t effectively use them for triangulation.

Here’s a handy-dandy summary matching/triangulation checklist for you to use as you work through your matches.

  • You inherit half of each of your parents’ DNA. There is no other place for you to obtain or inherit your DNA. There is no DNA fairy sprinkling you with DNA from another source:)
  • DNA does NOT skip generations, although in occasional rare circumstances, it may appear that this happened. In this situation, it’s incumbent upon you, the genealogist, to PROVE that an exception has occurred if you really believe it has. Those circumstances might be pedigree collapse or perhaps imputation. You’ll need to compare matches at vendors who provide a chromosome browser, triangulation, and full shared match list information. Never assume that you are the exception without hard and fast proof. We all know about assume, right?
  • Your siblings inherit half of your parents’ DNA too, but not the same exact half of your parent’s DNA that you other siblings did (unless they are identical twins.) You may inherit the exact same DNA from either or both of your parents on certain segments.
  • Your matches may match your parents on different or an additional segment that you did not inherit.
  • Every segment has an individual history. Evaluate every matching segment separately. One matching segment with someone could be maternal, one paternal, and one identical by chance.
  • You can confirm matches as valid if your match matches one of your parents, and you match one of your match’s parents. Parental Phasing is when your match matches your parent. Parental Cross-Matching is when you both match one of each other’s parents. To be complete, both people who match each other need to match one of the parents of the other person. This rule still holds even if you have a known common ancestor. I can’t even begin to tell you how many times I’ve been fooled.
  • 15-20% (or more with endogamy) of your matches will be identical by chance because either your DNA or your match’s DNA aligns in such a way that while they match you, they don’t match either of your parents.
  • Your siblings, aunts, and uncles will often inherit the same DNA as you – which means that identical by chance matches will also match them. That’s why we don’t use close family members for triangulation. We do utilize close family members to generate common match hints. (Remember the 20 cM shared match caveat at Ancestry)
  • While your siblings, aunts, and uncles are too close to use for triangulation, they are wonderful to identify ancestral matches. Some of their matches will match you as well, and some will not because your close family members inherited segments of your ancestor’s DNA that you did not. Everyone should test their oldest family members.
  • Triangulate your close family member’s matches separately from your own to shed more light on your ancestors.
  • Endogamy may interfere with parental phasing, meaning you may match because you and/or your match may have inherited some of the same DNA segment(s) from both sides of your tree and/or more DNA than might otherwise be expected.
  • Pedigree collapse needs to be considered when using parental phasing, especially when the same ancestor appears on both sides of your family tree. You may share more DNA with a match than expected.
  • Conversely, with pedigree collapse, your match may not match your parents, or vice versa, if a segment happens to have recombined in you in a way that drops the matching segments of your parents beneath the vendor’s match threshold.
  • While you will match all of your second cousins, you will only match approximately 90% of your third cousins and proportionally fewer as your relationship reaches further back in time.
  • Not being a DNA match with someone does NOT mean you’re NOT related to them, unless of course, you’re a second cousin (2C) or closer. It simply means you don’t carry any common ancestral segments above vendor thresholds.
  • At 2C or closer, if you’re not a DNA match, other alternative situations need to be considered – including the transfer/upload of the wrong person’s DNA file.
  • Imputation, a scientific process required of vendors may interfere with matching, especially in more distant relatives who have tested on different platforms.
  • Imputation artifacts will be less obvious when people are more closely related, meaning closer relatives can be expected to match on more and larger segments and imputation errors make less difference.
  • Imputation will not cause close relatives, meaning 2C or closer, to not match each other.
  • In addition to not supporting segment matching information, Ancestry down-weights some segments, removes some matching DNA, and does not show shared matches below 20cM, causing some people to misinterpret their lack of common matches in various ways.
  • To resolve questions about matching issues at Ancestry, testers can transfer/upload their DNA files to MyHeritage, FamilyTreeDNA, and GEDmatch and look for consistent matches on the same segment. Start and end locations may vary to some extent between vendors, but the segment size should be basically in the same location and roughly the same size.
  • GEDmatch does not use imputation but allows larger non-matching segments to combine as a single segment which sometimes causes extremely “generous” matches. GEDmatch matching is less reliable than FamilyTreeDNA or MyHeritage, but you can adjust the matching thresholds.
  • The best situation for matching is for both people to test at the same vendor who supports and provides segment data and a chromosome browser such as 23andMe, FamilyTreeDNA, or MyHeritage.
  • Siblings cannot be used for triangulation because the most recent common ancestor (MRCA) between you and your siblings is your parents. Therefore, the “three” people in the triangulation group is reduced to two lines immediately.
  • Uncles and aunts should not be used for triangulation because the most recent common ancestors between you and your aunts and uncles are your grandparents.
  • Conversely, you should not consider triangulating with siblings and close family members of your matches as proof of an ancestral relationship.
  • A triangulation group of 3 people is only confirmation as far back as when two of those people’s lines converge and reach a common ancestor.
  • Identical by chance (IBC) matching occurs when DNA from the maternal and paternal sides are mixed positionally in the child to resemble a maternal/paternal side match with someone else.
  • Identical by chance DNA admixture (when compared to a match) could have occurred in your parents or grandparent’s generation, or earlier, so the further back in time that people in a triangulation group reach, the more reliable the triangulation group is likely to be.
  • The larger the segments and/or the triangulation group, the stronger the evidence for a specific confirmed common ancestor.
  • Early families with a very large number of descendants may have many matching and triangulated members, even 9 or 10 generations later.
  • While exactly 50% of each ancestor’s DNA is not passed in each generation, on average, you will carry 7 cM of your ancestors 10 generations back in your tree. However, you may carry more, or none.
  • The percentage of matching descendants decreases with each generation beyond great-grandparents.
  • The ideal situation for triangulation is a significant number of people, greater than three, who match on the same reasonably sized segment (7 cM/500 SNP or larger) and descend from the same ancestor (or ancestral couple) through different children whose spouses in descendant generations are not also related.
  • This means that tree completion is an important factor in match/triangulation reliability.
  • Triangulating through different children of the ancestral couple makes it significantly less likely that a different unknown common ancestor is contributing that segment of DNA – like an unknown wife in a descendant generation.

Whew!!!

The Bottom Line

Here’s the bottom line.

  1. Don’t use close relatives to triangulate.
  2. Use parents for Parental Phasing.
  3. Use Parental Cross-Matching when possible.
  4. Use close relatives to look for shared common matches that may lead to triangulation possibilities.
  5. Triangulate your close relatives’ DNA in addition to your own for bonus genealogical information. They will match people that you don’t.
  6. For the most reliable triangulation results, use the most distant relatives possible, descended through different children of the common ancestral couple.
  7. Keep this checklist of best practices, cautions, and caveats handy and check the list as necessary when evaluating the strength of any match or triangulation group. It serves as a good reminder for what to check if something seems “off” or unusual.

Feel free to share and pass this article (and checklist) on to your genealogy buddies and matches as you explain triangulation and collaborate on your genealogy.

Have fun!!!

_____________________________________________________________

Disclosure

I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

DNA Purchases and Free Transfers

Genealogy Products and Services

Books

Genealogy Research

How to Download Your DNA Matching Segment Data and Why You Should

There are two or three types of data that testers may be able to download from DNA testing sites. Genealogy customers need to periodically download as much as possible.

  1. Raw data files needed for transferring DNA files from the company where you tested to other testing or analysis/comparison sites such as FamilyTreeDNA, MyHeritage, and GEDmatch for matching and other tools.
  2. Matching segment files which detail your matches, segment by segment with people whom you match.
  3. Match information files that provide you with additional information about your matches. What’s included varies by vendor.

This type of information is not uniformly available from all vendors, but is available as follows:

Vendor Raw Data File Matching Segment File Match Information File
FamilyTreeDNA Yes Yes Yes
MyHeritage Yes Yes Yes
23andMe Yes Yes Yes
Ancestry Yes No No
GedMatch Not a testing company, so no Yes Yes

I have provided step-by-step information about how to download your raw DNA data files and upload them to other vendors in a series of articles that you can find here.

Some of the answers in the table above need caveats because each vendor is different. Let’s take a look.

Matching Segment Files

In this article, I’ll provide information about how to download your matching segment and match information file(s).

Unfortunately, Ancestry does not provide any segment data at all, nor do they provide a way to download your match information. Third-party tools that did this for you have been banned by Ancestry, under threat of legal action, so this information is no longer available to Ancestry customers.

You can’t obtain this information from Ancestry, but you can transfer your DNA file to other vendors such as FamilyTreeDNA, MyHeritage and the third-party site, GEDmatch where you’ll receive additional matches. Some Ancestry matches will have transferred elsewhere as well, and you can take advantage of your matching segment information.

Why Do I Want a Matching Segment File?

The matching segment file provides you with information about exactly how and where you match each person.

Here’s an example that includes the match name, chromosome, start and end location of the match along with the total number of CentiMorgans (cM) and total SNPs in the matching segment. Your matching segment file consists of hundreds/thousands of rows of this information.

Determining who matches you on the same segment is important because it facilitates the identification of common ancestors. Segment matching is also the first step in triangulation which allows you to confirm descent from common ancestors with your matches.

I wrote about triangulation at each vendor in the following articles:

Matching and Triangulation help you sort out legitimate matches, and which ancestors that DNA segment comes from.

Sorting For Legitimate Matches

On each segment location of your DNA, you will match:

  • People from your Mom’s side
  • People from your Dad’s side
  • People that are identical by chance (IBC) where they match you because part of the DNA from your Mom’s side and part from your Dad’s side just happens to look like their DNA (or vice versa.)

You can see how matching works in this example of 10 DNA locations. You inherited half of your Mom’s DNA and half of your Dad’s.

  • Legitimate maternal matches to you on this segment will have all As in this location.
  • Legitimate paternal matches to you will have all Cs in this location.
  • Identical by chance matches will match you, because they have the same DNA as both of your parents that you carry – interspersed. They will not match either of your parents individually.

IBC matches DO technically match you, but accidentally. In other words, they are identical by chance (IBC) because they just happen to match the DNA of both of your parents intermixed. Conversely, you can match the DNA of their parents intermixed as well. Regardless of why, they are not a legitimate maternal or paternal match to you.

For example, you can see that the identical by chance (IBC) match to you, above, won’t match the legitimate maternal or legitimate paternal matches.

When comparing your matches on any segment, you’ll wind up with a group of people who match you and each other on your maternal side, a group on your paternal side, and “everyone else” who is IBC.

I wrote about IBD, identical by descent DNA and IBC, identical by chance DNA and how that works, here.

A downloadable segment match file allows you to sort all of your matches by chromosome and segment. That’s the first step in determining if your matches match each other – which is how to determine if people are legitimate matches or IBC.

Additionally, these files allow you to utilize features at DNAPainter along with the tools at DNAGedcom and Genetic Affairs.

Match Information File

There’s a second file you’ll want to download as well except at 23andMe who includes all of the information in one file. You’ll want to download these files from each vendor at the same time so they are coordinated and include the same matches from the same time.

Downloading the second file, your match information, provides additional information which will be helpful for your genealogy. The information in this file varies by vendor, but includes items such as, but not limited to:

  • Tree link
  • Haplogroup
  • Match date
  • Predicted Relationship Range
  • Actual Relationship
  • Total shared cM
  • Longest segment cM
  • Maternal or paternal bucket (FamilyTreeDNA)
  • Notes
  • Email
  • Family Surnames
  • Location
  • Percent of shared DNA

You never know when vendors are going to change something that will affect your matches, like 23andMe did last fall, so it’s a good idea to download periodically.

Downloading your segment match and match information files are free, so let’s do this.

Downloading Your Segment Match & Information Files

FamilyTreeDNA

Sign on to your account.

click images to enlarge

Under your Family Finder Autosomal DNA test results, click on Chromosome Browser.

On the chromosome browser page, at the top right, click on Download All Segments.

Caveat – if you access the chromosome browser through the Family Finder match page, shown below, you will receive the segment matches ONLY for the people you have selected.

After selecting specific matches, as shown above, the option on the chromosome browser page will only say “Download Segments.” It does NOT say “Download All Segments.”

Clicking on this link only downloads the segments that you match with those people, so always be sure to access “Download ALL Segments” directly through the chromosome browser selection on your Autosomal DNA Family Finder menu without going to your match page and selecting specific matches.

The segment download file includes only the segments, but not additional information, such as which side, maternal or paternal, those matches are bucketed to, surnames and so forth. You need to download a second file.

To download additional information about your matches, scroll to the very bottom of your Family Finder match page and click on either Download Matches or Download Filtered matches. If you’ve used a filter such as maternal or paternal, you’ll receive only those matches, so be sure no filters are in use to download all of your matches’ information.

Your reports will be downloaded to your computer, so save them someplace where you can find them.

MyHeritage

Sign in to your account and click on the DNA tab, then DNA Matches.

At the far right-hand side, you’ll see three little dots. Click on the dots and you’ll see the options to export both the entire DNA Matches list and the shared DNA segment info for all DNA Matches.

You’ll want to download both. The first file Is the DNA matches list.

To download your segment matches, select the second option, “Export shared DNA segment info…”

Your files will be emailed to you.

23andMe

At 23andMe, sign on to your account and click on “DNA Relatives” under the Ancestry tab.

You’ll see your list of matches. Scroll to the very bottom where you’ll see the link to “Download aggregate data.”

23andMe combines your segment and match information in one file.

Remember that at 23andMe, your matches are limited to 2000 (unless you’re a V5 subscriber), minus the number of people who have not opted in to Relative Sharing. Additionally, there will be a number of people in the download file whose names appear, but who don’t have any segment data. Those people opted-in to Relative Sharing, but not to share segment information.

For example, my download file has 2827 rows. Of those, 1769 are unique individuals, meaning that I have matches with multiple segments for 1058 people. This means that of my 2000 allowed matches, 231 (or more) did not opt-in for Relative Sharing. The “or more” means that 23andMe does not roll matches off the list if you have communicated with the person, so some people may actually have more than 2000 matches. It’s impossible to know how 23andMe approaches calculations in this case.

Of those 1769 unique individuals on my match list, 257, or 15% did not share segment information. I’d sure like for those to be automatically rolled off and replaced with the next 257 who do share. 1512 or roughly three-quarters, 75%, of my 2000 allowed matches are useful for genealogy.

Initially, when 23andMe made their changes last fall, they were reportedly limiting the download file number to 1000, but they have reversed that policy on the V3 and V4 chips. I downloaded files from both chip versions to confirm that’s true.

I don’t have the V5 chip subscription level, nor am I going to retest to do that, so I don’t know if V5 subscribers receive all 5000 of the allowed matches in their download file.

This is the perfect example of why it’s a good idea to download your match files periodically. 23andMe is the only testing vendor that restricts your matches and when they roll off your list, they are irretrievable.

Aside from that, safe is better than sorry. You never know when something will change at a vendor and you’ll wish you had downloaded your match files earlier.

GedMatch

GedMatch, a third-party vendor, provides lots of tools but isn’t intuitive and provides almost no tutorial or information about how to navigate or use their site. There are some YouTube videos and Kitty Cooper has written several how-to articles. GEDmatch has promised a facelift soon.

GEDmatch provides many tools for free, along with a Tier1 level which provides advanced features by subscription.

At GEDmatch, you can see up to 2000 matches for free, but you must be a Tier 1 subscription member to download your matches – and the download is restricted to your top 1000 matches.

There are two Tier 1 one-to-many comparison options that are very similar. For either, you’ll enter your kit number and make your selection. Given that you’re restricted to 1000 in the download, there is no reason to search for more than 1000 kits.

click to enlarge

Then, click on Visualization options

You will then see the list of visualization options which includes “List/CSV.”

Clicking on “List/CSV” provides you with options.

click to enlarge

You’ll want to select the Matched Segment List, and you can either select “Prevent Hard Breaks,” or not. Allowing hard breaks means that small non-matching regions between two matching segments is not ignored, and the two segments are reported as two separate segments – if they are large enough to be reported.

If you prevent hard breaks, non-matching regions of less than 500,000 thousand base positions are ignored, creating one larger blended segment. It’s my preference to allow hard breaks because I’ve seen too many instances of erroneously “blended” segments.

When your matching segment file is complete, you will be prompted to download to your computer.

Thanks to Genetic Affairs, I discovered an alternate way to obtain more than 1000 downloaded matches from GEDmatch.

GEDmatch Alternative Methodology

Genetic Affairs suggests using the DNA Segment Search with a minimum of 5000 kits, and to enable the option to “Prevent Hard Breaks.”

Do not close the session while GedMatch is processing or you’ll need to restart your query.

When finished click “Here” to download the file to your system.

Now you’re ready for part 2.

Next, you’ll want to select the Triangulation feature.

These functions take time, so you’ll be watching as the counter increases. Or maybe go eat dinner or research some genealogy.

I can hear the “Jeopardy countdown music

When finished, click on “Here” to download this second file.

Whew! Now you should have your segment and match information files from each company that supports this information and provides downloads.

Saving Files

I generally save my files by vendor and date. However, if you’re going to use the files for a special project – you may want to make a copy elsewhere. For example, I’m going to use these files for Genetic Affairs’ AutoSegment feature, so I’ve downloaded fresh files from each vendor on the same date and made a separate copy, stored in my Genetic Affairs folder. I’ll let you know how that goes😊

Bottom Line

  • Test at vendors that don’t accept transfers. Ancestry and 23andMe
  • Test at or transfer to the rest. FamilyTreeDNA, MyHeritage and GEDmatch
  • Unlock or subscribe to the advanced tools that include chromosome browsers, ethnicity, and more, depending on the vendor. FamilyTreeDNA, MyHeritage, GEDmatch
  • Upload or create trees at each vendor (except 23andMe who doesn’t support trees.)
  • Download as much information as you can from each vendor.
  • Work your matches through shared (in common with) matches, trees, segments, and clusters!

Have fun!!!

_____________________________________________________________

Disclosure

I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

DNA Purchases and Free Transfers

Genealogy Products and Services

Books

Genealogy Research

Concepts: Inheritance

Inheritance.

What is it?

How does it work?

I’m not talking about possessions – but about the DNA that you receive from your parents, and their parents.

The reason that genetic genealogy works is because of inheritance. You inherit DNA from your parents in a known and predictable fashion.

Fortunately, we have more than one kind of DNA to use for genealogy.

Types of DNA

Females have 3 types of DNA and males have 4. These different types of DNA are inherited in various ways and serve different genealogical purposes.

Males Females
Y DNA Yes No
Mitochondrial DNA Yes Yes
Autosomal DNA Yes Yes
X Chromosome Yes, their mother’s only Yes, from both parents

Different Inheritance Paths

Different types of DNA are inherited from different ancestors, down different ancestral paths.

Inheritance Paths

The inheritance path for Y DNA is father to son and is inherited by the brother, in this example, from his direct male ancestors shown by the blue arrow. The sister does not have a Y chromosome.

The inheritance path for the red mitochondrial DNA for both the brother and sister is from the direct matrilineal ancestors, only, shown by the red arrow.

Autosomal DNA is inherited from all ancestral lines on both the father’s and mother’s side of your tree, as illustrated by the broken green arrow.

The X chromosome has a slightly different inheritance path, depending on whether you are a male or female.

Let’s take a look at each type of inheritance, how it works, along with when and where it’s useful for genealogy.

Autosomal DNA

Autosomal DNA testing is the most common. It’s the DNA that you inherit from both of your parents through all ancestral lines back in time several generations. Autosomal DNA results in matches at the major testing companies such as FamilyTreeDNA, MyHeritage, Ancestry, and 23andMe where testers view trees or other hints, hoping to determine a common ancestor.

How does autosomal DNA work?

22 autosomes

Every person has two each of 22 chromosomes, shown above, meaning one copy is contributed by your mother and one copy by your father. Paired together, they form the two-sided shape we are familiar with.

For each pair of chromosomes, you receive one from your father, shown with a blue arrow under chromosome 1, and one from your mother, shown in red. In you, these are randomly combined, so you can’t readily tell which piece comes from which parent. Therein lies the challenge for genealogy.

This inheritance pattern is the same for all chromosomes, except for the 23rd pair of chromosomes, at bottom right, which determined the sex of the child.

The 23rd chromosome pair is inherited differently for males and females. One copy is the Y chromosome, shown in blue, and one copy is the X, shown in red. If you receive a Y chromosome from your father, you’re a male. If you receive an X from your father, you’re a female.

Autosomal Inheritance

First, let’s talk about how chromosomes 1-22 are inherited, omitting chromosome 23, beginning with grandparents.

Inheritance son daughter

Every person inherits precisely half of each of their parents’ autosomal DNA. For example, you will receive one copy of your mother’s chromosome 1. Your mother’s chromosome 1 is a combination of her mother’s and father’s chromosome 1. Therefore, you’ll receive ABOUT 25% of each of your grandparents’ chromosome 1.

Inheritance son daughter difference

In reality, you will probably receive a different amount of your grandparent’s DNA, not exactly 25%, because your mother or father will probably contribute slightly more (or less) of the DNA of one of their parents than the other to their offspring.

Which pieces of DNA you inherit from your parents is random, and we don’t know how the human body selects which portions are and are not inherited, other than we know that large pieces are inherited together.

Therefore, the son and daughter won’t inherit the exact same segments of the grandparents’ DNA. They will likely share some of the same segments, but not all the same segments.

Inheritance maternal autosomalYou’ll notice that each parent carries more of each color DNA than they pass on to their own children, so different children receive different pieces of their parents’ DNA, and varying percentages of their grandparents’ DNA.

I wrote about a 4 Generation Inheritance Study, here.

Perspective

Keep in mind that you will only inherit half of the DNA that each of your parents carries.

Looking at a chromosome browser, you match your parents on all of YOUR chromosomes.

Inheritance parental autosomal

For example, this is me compared to my father. I match my father on either his mother’s side, or his father’s side, on every single location on MY chromosomes. But I don’t match ALL of my father’s DNA, because I only received half of what he has.

From your parents’ perspective, you only have half of their DNA.

Let’s look at an illustration.

Inheritance mom dad

Here is an example of one of your father’s pairs of chromosomes 1-22. It doesn’t matter which chromosome, the concepts are the same.

He inherited the blue chromosome from his father and the pink chromosome from his mother.

Your father contributed half of his DNA to you, but that half is comprised of part of his father’s chromosome, and part of his mother’s chromosome, randomly selected in chunks referred to as segments.

Inheritance mom dad segments

Your father’s chromosomes are shown in the upper portion of the graphic, and your chromosome that you inherited from you father is shown below.

On your copy of your father’s chromosome, I’ve darkened the dark blue and dark pink segments that you inherited from him. You did not receive the light blue and light pink segments. Those segments of DNA are lost to your line, but one of your siblings might have inherited some of those pieces.

Inheritance mom dad both segments

Now, I’ve added the DNA that you inherited from your Mom into the mixture. You can see that you inherited the dark green from your Mom’s father and the dark peach from your Mom’s mother.

Inheritance grandparents dna

These colored segments reflect the DNA that you inherited from your 4 grandparents on this chromosome.

I often see questions from people wondering how they match someone from their mother’s side and someone else from their father’s side – on the same segment.

Understanding that you have a copy of the same chromosome from your mother and one from your father clearly shows how this happens.

Inheritance match 1 2

You carry a chromosome from each parent, so you will match different people on the same segment. One match is to the chromosome copy from Mom, and one match is to Dad’s DNA.

Inheritance 4 gen

Here is the full 4 generation inheritance showing Match 1 matching a segment from your Dad’s father and Match 2 matching a segment from your Mom’s father.

Your Parents Will Have More Matches Than You Do

From your parents’ perspective, you will only match (roughly) half of the DNA with other people that they will match. On your Dad’s side, on segment 1, you won’t match anyone pink because you didn’t inherit your paternal grandmother’s copy of segment 1, nor did you inherit your maternal grandmother’s segment 1 either. However, your parents will each have matches on those segments of DNA that you didn’t inherit from them.

From your perspective, one or the other of your parents will match ALL of the people you match – just like we see in Match 1 and Match 2.

Matching you plus either of your parents, on the same segment, is exactly how we determine whether a match is valid, meaning identical by descent, or invalid, meaning identical by chance. I wrote about that in the article, Concepts: Identical by…Descent, State, Population and Chance.

Inheritance on chromosomes 1-22 works in this fashion. So does the X chromosome, fundamentally, but the X chromosome has a unique inheritance pattern.

X Chromosome

The X chromosome is inherited differently for males as compared to females. This is because the 23rd pair of chromosomes determines a child’s sex.

If the child is a female, the child inherits an X from both parents. Inheritance works the same way as chromosomes 1-22, conceptually, but the inheritance path on her father’s side is different.

If the child is a male, the father contributes a Y chromosome, but no X, so the only X chromosome a male has is his mother’s X chromosome.

Males inherit X chromosomes differently than females, so a valid X match can only descend from certain ancestors on your tree.

inheritance x fan

This is my fan chart showing the X chromosome inheritance path, generated by using Charting Companion. My father’s paternal side of his chart is entirely blank – because he only received his X chromosome from his mother.

You’ll notice that the X chromosome can only descend from any male though his mother – the effect being a sort of checkerboard inheritance pattern. Only the pink and blue people potentially contributed all or portions of X chromosomes to me.

This can actually be very useful for genealogy, because several potential ancestors are immediately eliminated. I cannot have any X chromosome segment from the white boxes with no color.

The X Chromsome in Action

Here’s an X example of how inheritance works.

Inheritance X

The son inherits his entire X chromosome from his mother. She may give him all of her father’s or mother’s X, or parts of both. It’s not uncommon to find an entire X chromosome inherited. The son inherits no X from his father, because he inherits the Y chromosome instead.

Inheritance X daughter

The daughter inherits her father’s X chromosome, which is the identical X chromosome that her father inherited from his mother. The father doesn’t have any other X to contribute to his daughter, so like her father, she inherits no portion of an X chromosome from her paternal grandfather.

The daughter also received segments of her mother’s X that her mother inherited maternally and paternally. As with the son, the daughter can receive an entire X chromosome from either her maternal grandmother or maternal grandfather.

This next illustration ONLY pertains to chromosome 23, the X and Y chromosomes.

Inheritance x y

You can see in this combined graphic that the Y is only inherited by sons from one direct line, and the father’s X is only inherited by his daughter.

X chromosome results are included with autosomal results at both Family Tree DNA and 23andMe, but are not provided at MyHeritage. Ancestry, unfortunately, does not provide segment information of any kind, for the X or chromosomes 1-22. You can, however, transfer the DNA files to Family Tree DNA where you can view your X matches.

Note that X matches need to be larger than regular autosomal matches to be equally as useful due to lower SNP density. I use 10-15 cM as a minimum threshold for consideration, equivalent to about 7 cM for autosomal matches. In other words, roughly double the rule of thumb for segment size matching validity.

Autosomal Education

My blog is full of autosomal educational articles and is fully keyword searchable, but here are two introductory articles that include information from the four major vendors:

When to Purchase Autosomal DNA Tests

Literally, anytime you want to work on genealogy to connect with cousins, prove ancestors or break through brick walls.

  • Purchase tests for yourself and your siblings if both parents aren’t living
  • Purchase tests for both parents
  • Purchase tests for all grandparents
  • Purchase tests for siblings of your parents or your grandparents – they have DNA your parents (and you) didn’t inherit
  • Test all older generation family members
  • If the family member is deceased, test their offspring
  • Purchase tests for estimates of your ethnicity or ancestral origins

Y DNA

Y DNA is only inherited by males from males. The Y chromosome is what makes a male, male. Men inherit the Y chromosome intact from their father, with no contribution from the mother or any female, which is why men’s Y DNA matches that of their father and is not diluted in each generation.

Inheritance y mtdna

If there are no adoptions in the line, known or otherwise, the Y DNA will match men from the same Y DNA line with only small differences for many generations. Eventually, small changes known as mutations accrue. After many accumulated mutations taking several hundred years, men no longer match on special markers called Short Tandem Repeats (STR). STR markers generally match within the past 500-800 years, but further back in time, they accrue too many mutations to be considered a genealogical-era match.

Family Tree DNA sells this test in 67 and 111 marker panels, along with a product called the Big Y-700.

The Big Y-700 is the best-of-class of Y DNA tests and includes at least 700 STR markers along with SNPs which are also useful genealogically plus reach further back in time to create a more complete picture.

The Big Y-700 test scans the entire useful portion of the Y chromosome, about 15 million base pairs, as compared to 67 or 111 STR locations.

67 and 111 Marker Panel Customers Receive:

  • STR marker matches
  • Haplogroup estimate
  • Ancestral Origins
  • Matches Map showing locations of the earliest known ancestors of matches
  • Haplogroup Origins
  • Migration Maps
  • STR marker results
  • Haplotree and SNPs
  • SNP map

Y, mitochondrial and autosomal DNA customers all receive options for Advanced Matching.

Big Y-700 customers receive, in addition to the above:

  • All of the SNP markers in the known phylotree shown publicly, here
  • A refined, definitive haplogroup
  • Their place on the Block Tree, along with their matches
  • New or unknown private SNPs that might lead to a new haplogroup, or genetic clan, assignment
  • 700+ STR markers
  • Matching on both the STR markers and SNP markers, separately

Y DNA Education

I wrote several articles about understanding and using Y DNA:

When to Purchase Y DNA Tests

The Y DNA test is for males who wish to learn more about their paternal line and match against other men to determine or verify their genealogical lineage.

Women cannot test directly, but they can purchase the Y DNA test for men such as fathers, brothers, and uncles.

If you are purchasing for someone else, I recommend purchasing the Big Y-700 initially.

Why purchase the Big Y-700, when you can purchase a lower level test for less money? Because if you ever want to upgrade, and you likely will, you have to contact the tester and obtain their permission to upgrade their test. They may be ill, disinterested, or deceased, and you may not be able to upgrade their test at that time, so strike while the iron is hot.

The Big Y-700 provides testers, by far, the most Y DNA data to work (and fish) with.

Mitochondrial DNA

Inheritance mito

Mitochondrial DNA is passed from mothers to both sexes of their children, but only females pass it on.

In your tree, you and your siblings all inherit your mother’s mitochondrial DNA. She inherited it from her mother, and your grandmother from her mother, and so forth.

Mitochondrial DNA testers at FamilyTreeDNA receive:

  • A definitive haplogroup, thought of as a genetic clan
  • Matching
  • Matches Map showing locations of the earliest know ancestors of matches
  • Personalized mtDNA Journey video
  • Mutations
  • Haplogroup origins
  • Ancestral origins
  • Migration maps
  • Advanced matching

Of course, Y, mitochondrial and autosomal DNA testers can join various projects.

Mitochondrial DNA Education

I created a Mitochondrial DNA page with a comprehensive list of educational articles and resources.

When to Purchase Mitochondrial DNA Tests

Mitochondrial DNA can be valuable in terms of matching as well as breaking down brick walls for women ancestors with no surnames. You can also use targeted testing to prove, or disprove, relationship theories.

Furthermore, your mitochondrial DNA haplogroup, like Y DNA haplogroups, provides information about where your ancestors came from by identifying the part of the world where they have the most matches.

You’ll want to purchase the mtFull sequence test provided by Family Tree DNA. Earlier tests, such as the mtPlus, can be upgraded. The full sequence test tests all 16,569 locations on the mitochondria and provides testers with the highest level matching as well as their most refined haplogroup.

The full sequence test is only sold by Family Tree DNA and provides matching along with various tools. You’ll also be contributing to science by building the mitochondrial haplotree of womankind through the Million Mito Project.

Combined Resources for Genealogists

You may need to reach out to family members to obtain Y and mitochondrial DNA for your various genealogical lines.

For example, the daughter in the tree below, a genealogist, can personally take an autosomal test along with a mitochondrial test for her matrilineal line, but she cannot test for Y DNA, nor can she obtain her paternal grandmother’s mitochondrial DNA directly by testing herself.

Hearts represent mitochondrial DNA, and stars, Y DNA.

Inheritance combined

However, our genealogist’s brother, father or grandfather can test for her father’s (blue star) Y DNA.

Her father or any of his siblings can test for her paternal grandmother’s (hot pink heart) mitochondrial DNA, which provides information not available from any other tester in this tree, except for the paternal grandmother herself.

Our genealogist’s paternal grandfather, and his siblings, can test for his mother’s (yellow heart) mitochondrial DNA.

Our genealogist’s maternal grandfather can test for his (green star) Y DNA and (red heart) mitochondrial DNA.

And of course, it goes without saying that every single generation upstream of the daughter, our genealogist, should all take autosomal DNA tests.

So, with several candidates, who can and should test for what?

Person Y DNA Mitochondrial Autosomal
Daughter No Y – can’t test Yes, her pink mother’s Yes – Test
Son Yes – blue Y Yes, his pink mother’s Yes – Test
Father Yes – blue Y Yes – his magenta mother’s Yes – Test
Paternal Grandfather Yes – blue Y – Best to Test Yes, his yellow mother’s – Test Yes – Test
Mother No Y – can’t test Yes, her pink mother’s Yes – Test
Maternal Grandmother No Y – can’t test Yes, her pink mother’s – Best to Test Yes – Test
Maternal Grandfather Yes – green Y – Test Yes, his red mother’s – Test Yes – Test

The best person/people to test for each of the various lines and types of DNA is shown bolded above…assuming that all people are living. Of course, if they aren’t, then test anyone else in the tree who carries that particular DNA – and don’t forget to consider aunts and uncles, or their children, as candidates.

If one person takes the Y and/or mitochondrial DNA test to represent a specific line, you don’t need another person to take the same test for that line. The only possible exception would be to confirm a specific Y DNA result matches a lineage as expected.

Looking at our three-generation example, you’ll be able to obtain a total of two Y DNA lines, three mitochondrial DNA lines, and 8 autosomal results, helping you to understand and piece together your family line.

You might ask, given that the parents and grandparents have all autosomally tested in this example, if our genealogist really needs to test her brother, and the answer is probably not – at least not today.

However, in cases like this, I do test the sibling, simply because I can learn and it may encourage their interest or preserve their DNA for their children who might someday be interested. We also don’t know what kind of advances the future holds.

If the parents aren’t both available, then you’ll want to test as many of your (and their) siblings as possible to attempt to recover as much of the parents’ DNA, (and matches) as possible.

Your family members’ DNA is just as valuable to your research as your own.

Increase Your Odds

Don’t let any of your inherited DNA go unused.

You can increase your odds of having autosomal matches by making sure you are in all 4 major vendor databases.

Both FamilyTreeDNA and MyHeritage accept transfers from 23andMe and Ancestry, who don’t accept transfers. Transferring and matching is free, and their unlock fees, $19 at FamilyTreeDNA, and $29 at MyHeritage, respectively, to unlock their advanced tools are both less expensive than retesting.

You’ll find easy-to-follow step-by-step transfer instructions to and from the vendors in the article DNA File Upload-Download and Transfer Instructions to and from DNA Testing Companies.

Order

You can order any of the tests mentioned above by clicking on these links:

Autosomal:

Transfers

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Disclosure

I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

DNA Purchases and Free Transfers

Genealogy Products and Services

Genealogy Research

Concepts: Chromosome Browser – What Is It, How Do I Use It, and Why Do I Care?

The goal of genetic genealogy is to utilize DNA matches to verify known ancestors and identify unknown ancestors.

A chromosome browser is a tool that allows testers to visualize and compare their DNA on each chromosome with that of their genetic matches. How to utilize and interpret that information becomes a little more tricky.

I’ve had requests for one article with all the information in one place about chromosome browsers:

  • What they are
  • How and when to use them
  • Why you’d want to

I’ve included a feature comparison chart and educational resource list at the end.

I would suggest just reading through this article the first time, then following along with your own DNA results after you understand the basic landscape. Using your own results is the best way to learn anything.

What Does a Chromosome Browser Look Like?

Here’s an example of a match to my DNA at FamilyTreeDNA viewed on their chromosome browser.

browser example.png

On my first 16 chromosomes, shown above, my 1C1R (first cousin once removed,) Cheryl, matches me where the chromosomes are painted blue. My chromosome is represented by the grey background, and her matching portion by the blue overlay.

Cheryl matches me on some portion of all chromosomes except 2, 6, and 13, where we don’t match at all.

You can select any one person, like Cheryl, from your match list to view on a chromosome browser to see where they match you on your chromosomes, or you can choose multiple matches, as shown below.

browser multiple example.png

I selected my 7 closest matches that are not my immediate family, meaning not my parents or children. I’m the background grey chromosome, and each person’s match is painted on top of “my chromosome” in the location where they match me. You see 7 images of my grey chromosome 1, for example, because each of the 7 people being compared to me are shown stacked below one another.

Everyplace that Cheryl matches me is shown on the top image of each chromosome, and our matching segment is shown in blue. The same for the second red copy of the chromosome, representing Don’s match to me. Each person I’ve selected to match against is shown by their own respective color.

You’ll note that in some cases, two people match me in the same location. Those are the essential hints we are looking for. We’ll be discussing how to unravel, interpret, and use matches in the rest of this article.

browser MyHeritage example.png

The chromosome browser at MyHeritage looks quite similar. However, I have a different “top 7” matches because each vendor has people who test on their platform who don’t test or transfer elsewhere.

Each vendor that supports chromosome browsers (FamilyTreeDNA, MyHeritage, 23andMe, and GedMatch) provides their own implementation, of course, but the fundamentals of chromosome browsers, how they work and what they are telling us is universal.

Why Do I Need a Chromosome Browser?

“But,” you might say, “I don’t need to compare my DNA with my matches because the vendors already tell me that I match someone, which confirms that we are related and share a common ancestor.”

Well, not exactly. It’s not quite that straightforward.

Let’s take a look at:

  • How and why people match
  • What matches do and don’t tell you
  • Both with and without a chromosome browser

In part, whether you utilize a chromosome browser or not depends on which of the following you seek:

  • A broad-brush general answer; yes or no, I match someone, but either I don’t know how are related, or have to assume why. There’s that assume word again.
  • To actually confirm and prove your ancestry, getting every ounce of value out of your DNA test.

Not everyone’s goals are the same. Fortunately, we have an entire toolbox with a wide range of tools. Different tools are better suited for different tasks.

People seeking unknown parents should read the article, Identifying Unknown Parents and Individuals Using DNA Matching because the methodology for identifying unknown parents is somewhat different than working with genealogy. This article focuses on genealogy, although the foundation genetic principles are the same.

If you’re just opening your DNA results for the first time, the article, First Steps When Your DNA Results are Ready – Sticking Your Toe in the Genealogy Water would be a great place to start.

Before we discuss chromosome browsers further, we need to talk about DNA inheritance.

Your Parents

Every person has 2 copies of each of their 22 chromosomes – one copy contributed by their mother and one copy contributed by their father. A child receives exactly half of the autosomal DNA of each parent. The DNA of each parent combines somewhat randomly so that you receive one chromosome’s worth of DNA from each of your parents, which is half of each parent’s total.

On each chromosome, you receive some portion of the DNA that each parent received from their ancestors, but not exactly half of the DNA from each individual ancestor. In other words, it’s not sliced precisely in half, but served up in chunks called segments.

Sometimes you receive an entire segment of an ancestor’s DNA, sometimes none, and sometimes a portion that isn’t equal to half of your parent’s segment.

browser inheritance.png

This means that you don’t receive exactly half of the DNA of each of your grandparents, which would be 25% each. You might receive more like 22% from one maternal grandparent and 28% from the other maternal grandparent for a total of 50% of the DNA you inherit from your parents. The other 50% of your DNA comes from the other parent, of course. I wrote about that here.

There’s one tiny confounding detail. The DNA of your Mom and Dad is scrambled in you, meaning that the lab can’t discern scientifically which side is which and can’t tell which pieces of DNA came from Mom and which from Dad. Think of a genetic blender.

Our job, using genetic genealogy, is to figure out which side of our family people who match us descend from – which leads us to our common ancestor(s).

Parallel Roads

For the purposes of this discussion, you’ll need to understand that the two copies you receive of each chromosome, one from each parent, have the exact same “addresses.” Think of these as parallel streets or roads with identical addresses on each road.

browser street.png

In the example above, you can see Dad’s blue chromosome and Mom’s red chromosome as compared to me. Of course, children and parents match on the full length of each chromosome.

I’ve divided this chromosome into 6 blocks, for purposes of illustration, plus the centromere where we generally find no addresses used for genetic genealogy.

In the 500 block, we see that the address of 510 Main (red bar) could occur on either Dad’s chromosome, or Mom’s. With only an address and nothing more, you have no way to know whether your match with someone at 510 Main is on Mom’s or Dad’s side, because both streets have exactly the same addresses.

Therefore, if two people match you, at the same address on that chromosome, like 510 Main Street, they could be:

  • Both maternal matches, meaning both descended from your mother’s ancestors, and those two people will also match each other
  • Both paternal matches, meaning both descended from your father’s ancestors, and those two people will also match each other
  • One maternal and one paternal match, and those two people will not match each other

Well then, how do we know which side of the family a match descends from, and how do we know if we share a common ancestor?

Good question!

Identical by Descent

If you and another person match on a reasonably sized DNA segment, generally about 7 cM or above, your match is probably “identical by descent,” meaning not “identical by chance.” In this case, then yes, a match does confirm that you share a common ancestor.

Identical by descent (IBD) means you inherited the piece of DNA from a common ancestor, inherited through the relevant parent.

Identical by chance (IBC) means that your mom’s and dad’s DNA just happens to have been inherited by you randomly in a way that creates a sequence of DNA that matches that other person. I wrote about both IBD and IBC here.

MMB stats by cM 2

This chart, courtesy of statistician Philip Gammon, from the article Introducing the Match-Maker-Breaker Tool for Parental Phasing shows the percentage of time we expect matches of specific segment sizes to be valid, or identical by descent.

Identical by Chance

How does this work?

How is a match NOT identical by descent, meaning that it is identical by chance and therefore not a “real” or valid match, a situation also known as a false positive?

browser inheritance grid.png

The answer involves how DNA is inherited.

You receive a chromosome with a piece of DNA at every address from both parents. Of course, this means you have two pieces of DNA at each address. Therefore people will match you on either piece of DNA. People from your Dad’s side will match you on the pieces you inherited from him, and people from your Mom’s side will match you on the pieces you inherited from her.

However, both of those matches have the same address on their parallel streets as shown in the illustration, above. Your matches from your mom’s side will have all As, and those from your dad’s side will have all Ts.

The problem is that you have no way to know which pieces you inherited from Mom and from Dad – at least not without additional information.

You can see that for 10 contiguous locations (addresses), which create an example “segment” of your DNA, you inherited all As from your Mom and all Ts from your Dad. In order to match you, someone would either need to have an A or a T in one of their two inherited locations, because you have an A and a T, both. If the other person has a C or a G, there’s no match.

Your match inherited a specific sequence from their mother and father, just like you did. As you can see, even though they do match you because they have either an A or a T in all 10 locations – the As and Ts did not all descend from either their mother or father. Their random inheritance of Ts and As just happens to match you.

If your match’s parents have tested, you won’t match either of their parents nor will they match either of your parents, which tells you immediately that this match is by chance (IBC) and not by descent (IBD), meaning this segment did not come from a common ancestor. It’s identical by chance and, therefore, a false positive.

If We Match Someone Else In Common, Doesn’t That Prove Identical by Descent?

Nope, but I sure wish it did!

The vendors show you who else you and your match both match in common, which provides a SUGGESTION as to your common ancestor – assuming you know which common ancestor any of these people share with you.

browser icw.png

However, shared matches are absolutely NOT a guarantee that you, your match, and your common matches all share the same ancestor, unless you’re close family. Your shared match could match you or your match through different ancestors – or could be identical by chance.

How can we be more confident of what matching is actually telling us?

How can we sort this out?

Uncertainties and Remedies

Here’s are 9 things you DON’T know, based on matching alone, along with tips and techniques to learn more.

  1. If your match to Person A is below about 20cM, you’ll need to verify that it’s a legitimate IBD match (not IBC). You can achieve this by determining if Person A also matches one of your parents and if you match one of Person A’s parents, if parents have tested.

Not enough parents have tested? An alternative method is by determining if you and Person A both match known descendants of the candidate ancestors ON THE SAME SEGMENT. This is where the chromosome browser enters the picture.

In other words, at least three people who are confirmed to descend from your presumptive common ancestor, preferably through at least two different children, must match on a significant portion of the same segment.

Why is that? Because every segment has its own unique genealogical history. Each segment can and often does lead to different ancestors as you move further back in time.

In this example, I’m viewing Buster, David, and E., three cousins descended from the same ancestral couple, compared to me on my chromosome browser. I’m the background grey, and they show in color. You can see that all three of them match me on at least some significant portion of the same segment of chromosome 15.

browser 3 cousins.png

If those people also match each other, that’s called triangulation. Triangulation confirms descent from a common ancestral source.

In this case, I already know that these people are related on my paternal side. The fact that they all match my father’s DNA and are therefore all automatically assigned to my paternal matching tab at Family Tree DNA confirms my paper-trail genealogy.

I wrote detailed steps for triangulation at Family Tree DNA, here. In a nutshell, matching on the same segment to people who are bucketed to the same parent is an automated method of triangulation.

Of course, not everyone has the luxury of having their parents tested, so testing other family members, finding common segments, and assigning people to their proper location in your tree facilitates confirmation of your genealogy (and automating triangulation.)

The ONLY way you can determine if people match you on the same segment, and match each other, is having segment information available to you and utilizing a chromosome browser.

browser MyHeritage triangulation.png

In the example above, the MyHeritage triangulation tool brackets matches that match you (the background grey) and who are all triangulated, meaning they all also match each other. In this case, the portion where all three people match me AND each other is bracketed. I wrote about triangulation at MyHeritage here.

  1. If you match several people who descend from the same ancestor, John Doe, for example, on paper, you CANNOT presume that your match to all of those people is due to a segment of DNA descended from John Doe or his wife. You may not match any of those people BECAUSE OF or through segments inherited from John Doe or his wife. You need segment information and a chromosome browser to view the location of those matches.

Assuming these are legitimate IBD matches, you may share another common line, known or unknown, with some or all of those matches.

It’s easy to assume that because you match and share matches in common with other people who believe they are descended from that same ancestor:

  • That you’re all matching because of that ancestor.
  • Even on the same segments.

Neither of those presumptions can be made without additional information.

Trust me, you’ll get yourself in a heap o’ trouble if you assume. Been there, done that. T-shirt was ugly.

Let’s look at how this works.

browser venn.png

Here’s a Venn diagram showing me, in the middle, surrounded by three of my matches:

  • Match 1 – Periwinkle, descends from Lazarus Estes and Elizabeth Vannoy
  • Match 2 – Teal, descends from Joseph Bolton and Margaret Claxton
  • Match 3 – Mustard, descends from John Y. Estes and Rutha Dodson

Utilizing a chromosome browser, autocluster software, and other tools, we can determine if those matches also match each other on a common segment, which means they triangulate and confirm common ancestral descent.

Of course, those people could match each other due to a different ancestor, not necessarily the one I share with them nor the ancestors I think we match through.

If they/we do all match because they descend from a common ancestor, they can still match each other on different segments that don’t match me.

I’m in the center. All three people match me, and they also match each other, shown in the overlap intersections.

Note that the intersection between the periwinkle (Match 1) and teal (Match 2) people, who match each other, is due to the wives of the children of two of my ancestors. In other words, their match to each other has absolutely nothing to do with their match to me. This was an “aha’ moment for me when I first realized this was a possibility and happens far more than I ever suspected.

The intersection of the periwinkle (Match 1) and mustard (Match 3) matches is due to the Dodson line, but on a different segment than they both share with me. If they had matched each other and me on the same segment, we would be all triangulated, but we aren’t.

The source of the teal (Match 2) to mustard (Match 3) is unknown, but then again, Match 3’s tree is relatively incomplete.

Let’s take a look at autocluster software which assists greatly with automating the process of determining who matches each other, in addition to who matches you.

  1. Clustering technology, meaning the Leeds method as automated by Genetic Affairs and DNAGedcom help, but don’t, by themselves, resolve the quandary of HOW people match you and each other.

People in a colored cluster all match you and each other – but not necessarily on the same segment, AND, they can match each other because they are related through different ancestors not related to your ancestor. The benefit of autocluster software is that this process is automated. However, not all of your matches will qualify to be placed in clusters.

browser autocluster.png

My mustard cluster above includes the three people shown in the chromosome browser examples – and 12 more matches that can be now be researched because we know that they are all part of a group of people who all match me, and several of whom match each other too.

My matches may not match each other for a variety of reasons, including:

  • They are too far removed in time/generations and didn’t inherit any common ancestral DNA.
  • This cluster is comprised of some people matching me on different (perhaps intermarried) lines.
  • Some may be IBC matches.

Darker grey boxes indicate that those people should be in both clusters, meaning the red and mustard clusters, because they match people in two clusters. That’s another hint. Because of the grid nature of clusters, one person cannot be associated with more than 2 clusters, maximum. Therefore, people like first cousins who are closely related to the tester and could potentially be in many clusters are not as useful in clusters as they are when utilizing other tools.

  1. Clusters and chromosome browsers are much less complex than pedigree charts, especially when dealing with many people. I charted out the relationships of the three example matches from the Venn diagram. You can see that this gets messy quickly, and it’s much more challenging to visualize and understand than either the chromosome browser or autoclusters.

Having said that, the ultimate GOAL is to identify how each person is related to you and place them in their proper place in your tree. This, cumulatively with your matches, is what identifies and confirms ancestors – the overarching purpose of genealogy and genetic genealogy.

Let’s take a look at this particular colorized pedigree chart.

Browser pedigree.png

click to enlarge

The pedigree chart above shows the genetic relationship between me and the three matches shown in the Venn diagram.

Four descendants of 2 ancestral couples are shown, above; Joseph Bolton and Margaret Claxton, and John Y. Estes and Rutha Dodson. DNA tells me that all 3 people match me and also match each other.

The color of the square (above) is the color of DNA that represents the DNA segment that I received and match with these particular testers. This chart is NOT illustrating how much DNA is passed in each generation – we already know that every child inherits half of the DNA of each parent. This chart shows match/inheritance coloring for ONE MATCHING SEGMENT with each match, ONLY.

Let’s look at Joseph Bolton (blue) and Margaret Claxton (pink). I descend through their daughter, Ollie Bolton, who married William George Estes, my grandfather. The DNA segment that I share with blue Match 2 (bottom left) is a segment that I inherited from Joseph Bolton (blue). I also carry inherited DNA from Margaret Claxton too, but that’s not the segment that I share with Match 2, which is why the path from Joseph Bolton to me, in this case, is blue – and why Match 2 is blue. (Just so you are aware, I know this segment descends from Joseph Bolton, because I also match descendants of Joseph’s father on this segment – but that generation/mtach is not shown on this pedigree chart.)

If I were comparing to someone else who I match through Margaret Claxton, I would color the DNA from Margaret Claxton to me pink in that illustration. You don’t have to DO this with your pedigree chart, so don’t worry. I created this example to help you understand.

The colored dots shown on the squares indicate that various ancestors and living people do indeed carry DNA from specific ancestors, even though that’s not the segment that matches a particular person. In other words, the daughter, Ollie, of Joseph Bolton and Margaret Claxton carries 50% pink DNA, represented by the pink dot on blue Ollie Bolton, married to purple William George Estes.

Ollie Bolton and William George Estes had my father, who I’ve shown as half purple (Estes) and half blue (Bolton) because I share Bolton DNA with Match 2, and Estes DNA with Match 1. Obviously, everyone receives half of each parent’s DNA, but in this case, I’m showing the path DNA descended for a specific segment shared with a particular match.

I’ve represented myself with the 5 colors of DNA that I carry from these particular ancestors shown on the pedigree chart. I assuredly will match other people with DNA that we’ve both inherited from these ancestors. I may match these same matches shown with DNA that we both inherited from other ancestors – for example, I might match Match 2 on a different segment that we both inherited from Margaret Claxton. Match 2 is my second cousin, so it’s quite likely that we do indeed share multiple segments of DNA.

Looking at Match 3, who knows very little about their genealogy, I can tell, based on other matches, that we share Dodson DNA inherited through Rutha Dodson.

I need to check every person in my cluster, and that I share DNA with on these same segment addresses to see if they match on my paternal side and if they match each other.

  1. At Family Tree DNA, I will be able to garner more information about whether or not my matches match each other by using the Matrix tool as well as by utilizing Phased Family Matching.

At Family Tree DNA, I determined that these people all match in common with me and Match 1 by using the “In Common With” tool. You can read more about how to use “In Common With” matching, here.

browser paternal.png

Family Matching phases the matches, assigning or bucketed them maternally or paternally (blue and red icons above), indicating, when possible, if these matches occur on the same side of your family. I wrote about the concept of phasing, here, and Phased Family Matching here and here.

Please note that there is no longer a limit on how distantly related a match can be in order to be utilized in Phased Family Matching, so long as it’s over the phase-matching threshold and connected correctly in your tree.

browser family tree dna link tree.png

Bottom line, if you can figure out how you’re related to someone, just add them into your tree by creating a profile card and link their DNA match to them by simply dragging and dropping, as illustrated above.

Linking your matches allows Family Matching to maternally or paternally assign other matches that match both you and your tree-linked matches.

If your matches match you on the same segment on the same parental side, that’s segment triangulation, assuming the matches are IBD. Phased Family Matching does this automatically for you, where possible, based on who you have linked in your tree.

For matches that aren’t automatically bucketed, there’s another tool, the Matrix.

browser matrix.png

In situations where your matches aren’t “bucketed” either maternally or paternally, the Matrix tool allows you to select matches to determine whether your matches also match each other. It’s another way of clustering where you can select specific people to compare. Note that because they also match each other (blue square) does NOT mean it’s on the same segment(s) where they match you. Remember our Venn diagram.

browser matrix grid.png

  1. Just because you and your matches all match each other doesn’t mean that they are matching each other because of the same ancestor. In other words, your matches may match each other due to another or unknown ancestor. In our pedigree example, you can see that the three matches match each other in various ways.
browser pedigree match.png

click to enlarge

  • Match 1 and Match 2 match each other because they are related through the green Jones family, who is not related to me.
  • Match 2 and Match 3 don’t know why they match. They both match me, but not on the same segment they share with each other.
  • Match 1 and Match 3 match through the mustard Dodson line, but not on the same segment that matches me. If we all did match on the same segment, we would be triangulated, but we wouldn’t know why Match 3 was in this triangulation group.
  1. Looking at a downloaded segment file of your matches, available at all testing vendors who support segment information and a chromosome browser, you can’t determine without additional information whether your matches also match each other.

browser chr 15.png

Here’s a group of people, above, that we’ve been working with on chromosome 15.

My entire match-list shows many more matches on that segment of chromosome 15. Below are just a few.

browser chr 15 all

Looking at seven of these people in the chromosome browser, we can see visually that they all overlap on part of a segment on chromosome 15. It’s a lot easier to see the amount of overlap using a browser as opposed to the list. But you can only view 7 at a time in the browser, so the combination of both tools is quite useful. The downloaded spreadsheet shows you who to select to view for any particular segment.

browser chr 15 compare.png

The critical thing to remember is that some matches will be from tyour mother’s side and some from your father’s side.

Without additional information and advanced tools, there’s no way to tell the difference – unless they are bucketed using Phased Family Matching at Family Tree DNA or bracketed with a triangulation bracket at MyHeritage.

At MyHeritage, this assumes you know the shared ancestor of at least one person in the triangulation group which effectively assigns the match to the maternal or paternal side.

Looking at known relatives on either side, and seeing who they also match, is how to determine whether these people match paternally or maternally. In this example below, the blue people are bucketed paternally through Phased Family Matching, the pink maternally, and the white rows aren’t bucketed and therefore require additional evaluation.

browser chr 15 maternal paternal.png

Additional research shows that Jonathan is a maternal match, but Robert and Adam are identical by chance because they don’t match either of my parents on this segment. They might be valid matches on other segments, but not this one.

browser chr 15 compare maternal paternal.png

  1. Utilizing relatives who have tested is a huge benefit, and why we suggest that everyone test their closest upstream relatives (meaning not children or grandchildren.) Testing all siblings is recommended if both parents aren’t available to test, because every child received different parts of their parents’ DNA, so they will match different relatives.

After deleting segments under 7 cM, I combine the segment match download files of multiple family members (who agree to allow me to aggregate their matches into one file for analysis) so that I can create a master match file for a particular family group. Sorting by match name, I can identify people that several of my cousins’ match.

browser 4 groups.png

This example is from a spreadsheet where I’ve combined the results of about 10 collaborating cousins to determine if we can break through a collective brick wall. Sorted by match name, this table shows the first 4 common matches that appear on multiple cousin’s match lists. Remember that how these people match may have nothing to do with our brick wall – or it might.

Note that while the 4 matches, AB, AG, ag, and A. Wayne, appear in different cousins’ match lists, only one shares a common segment of DNA: AB triangulates with Buster and Iona. This is precisely WHY you need segment information, and a chromosome browser, to visualize these matches, and to confirm that they do share a common DNA segment descended from a specific ancestor.

These same people will probably appear in autocluster groups together as well. It’s worth noting, as illustrated in the download example, that it’s much more typical for “in common with” matches to match on different segments than on the same segment. 

  1. Keep in mind that you will match both your mother and father on every single chromosome for the entire length of each chromosome.

browser parent matching.png

Here’s my kit matching with my father, in blue, and mother, in red on chromosomes 1 and 2.

Given that I match both of my parents on the full chromosome, inheriting one copy of my chromosome from each parent, it’s impossible to tell by adding any person at random to the chromosome browser whether they match me maternally or paternally. Furthermore, many people aren’t fortunate enough to have parents available for testing.

To overcome that obstacle, you can compare to known or close relatives. In fact, your close relatives are genetic genealogy gold and serve as your match anchor. A match that matches you and your close relatives can be assigned either maternally or paternally. I wrote about that here.

browser parent plus buster.png

You can see that my cousin Buster matches me on chromosome 15, as do both of my parents, of course. At this point, I can’t tell from this information alone whether Buster matches on my mother’s or father’s side.

I can tell you that indeed, Buster does match my father on this same segment, but what if I don’t have the benefit of my father’s DNA test?

Genealogy tells me that Buster matches me on my paternal side, through Lazarus Estes and Elizabeth Vannoy. Given that Buster is a relatively close family member, I already know how Buster and I are related and that our DNA matches. That knowledge will help me identify and place other relatives in my tree who match us both on the same segment of DNA.

To trigger Phased Family Matching, I placed Buster in the proper place in my tree at Family Tree DNA and linked his DNA. His Y DNA also matches the Estes males, so no adoptions or misattributed parental events have occurred in the direct Estes patrilineal line.

browser family tree dna tree.png

I can confirm this relationship by checking to see if Buster matches known relatives on my father’s side of the family, including my father using the “in common with” tool.

Buster matches my father as well as several other known family members on that side of the family on the same segments of DNA.

browser paternal bucket.png

Note that I have a total of 397 matches in common with Buster, 140 of which have been paternally bucketed, 4 of which are both (my children and grandchildren), and 7 of which are maternal.

Those maternal matches represent an issue. It’s possible that those people are either identical by chance or that we share both a maternal and paternal ancestor. All 7 are relatively low matches, with longest blocks from 9 to 14 cM.

Clearly, with a total of 397 shared matches with Buster, not everyone that I match in common with Buster is assigned to a bucket. In fact, 246 are not. I will need to take a look at this group of people and evaluate them individually, their genealogy, clusters, the matrix, and through the chromosome browser to confirm individual matching segments.

There is no single perfect tool.

Every Segment Tells a Unique History

I need to check each of the 14 segments that I match with Buster because each segment has its own inheritance path and may well track back to different ancestors.

browser buster segments.png

It’s also possible that we have unknown common ancestors due to either adoptions, NPEs, or incorrect genealogy, not in the direct Estes patrilineal line, but someplace in our trees.

browser buster paint.png

The best way to investigate the history and genesis of each segment is by painting matching segments at DNAPainter. My matching segments with Buster are shown painted at DNAPainter, above. I wrote about DNAPainter, here.

browser overlap.png

By expanding each segment to show overlapping segments with other matches that I’ve painted and viewing who we match, we can visually see which ancestors that segment descends from and through.

browser dnapainter walk back.png

These roughly 30 individuals all descend from either Lazarus Estes and Elizabeth Vannoy (grey), Elizabeth’s parents (dark blue), or her grandparents (burgundy) on chromosome 15.

As more people match me (and Buster) on this segment, on my father’s side, perhaps we’ll push this segment back further in time to more distant ancestors. Eventually, we may well be able to break through our end-of-line brick wall using these same segments by looking for common upstream ancestors in our matches’ trees.

Arsenal of Tools

This combined arsenal of tools is incredibly exciting, but they all depend on having segment information available and understanding how to use and interpret segment and chromosome browser match information.

One of mine and Buster’s common segments tracks back to end-of-line James Moore, born about 1720, probably in Virginia, and another to Charles Hickerson born about 1724. It’s rewarding and exciting to be able to confirm these DNA segments to specific ancestors. These discoveries may lead to breaking through those brick walls eventually as more people match who share common ancestors with each other that aren’t in my tree.

This is exactly why we need and utilize segment information in a chromosome browser.

We can infer common ancestors from matches, but we can’t confirm segment descent without specific segment information and a chromosome browser. The best we can do, otherwise, is to presume that a preponderance of evidence and numerous matches equates to confirmation. True or not, we can’t push further back in time without knowing who else matches us on those same segments, and the identity of their common ancestors.

The more evidence we can amass for each ancestor and ancestral couple, the better, including:

  • Matches
  • Shared “In Common With” Matches, available at all vendors.
  • Phased Family Matching at Family Tree DNA assigns matches to maternal or paternal sides based on shared, linked DNA from known relatives.
  • The Matrix, a Family Tree DNA tool to determine if matches also match each other. Tester can select who to compare.
  • ThruLines from Ancestry is based on a DNA match and shared ancestors in trees, but no specific segment information or chromosome browser. I wrote about ThruLines here and here.
  • Theories of Family Relativity, aka TOFR, at MyHeritage, based on shared DNA matches, shared ancestors in trees and trees constructed between matches from various genealogical records and sources. MyHeritage includes a chromosome browser and triangulation tool. I wrote about TOFR here and here.
  • Triangulation available through Phased Family Matching at Family Tree DNA and the integrated triangulation tool at MyHeritage. Triangulation between only 3 people at a time is available at 23andMe, although 23andMe does not support trees. See triangulation article links in the Resource Articles section below.
  • AutoClusters at MyHeritage (cluster functionality included), at Genetic Affairs (autoclusters plus tree reconstruction) and at DNAGedcom (including triangulation).
  • Genealogical information. Please upload your trees to every vendor site.
  • Y DNA and mitochondrial DNA confirmation, when available, through Family Tree DNA. I wrote about the 4 Kinds of DNA for Genetic Genealogy, here and the importance of Y DNA confirmation here, and how not having that information can trip you up.
  • Compiled segment information at DNAPainter allows you to combine segment information from various vendors, paint your maternal and paternal chromosomes, and visually walk segments back in time. Article with DNAPainter instructions is found here.

Autosomal Tool Summary Table

In order to help you determine which tool you need to use, and when, I’ve compiled a summary table of the types of tools and when they are most advantageous. Of course, you’ll need to read and understand about each tool in the sections above. This table serves as a reminder checklist to be sure you’ve actually utilized each relevant tool where and how it’s appropriate.

Family Tree DNA MyHeritage Ancestry 23andMe GedMatch
DNA Matches Yes Yes Yes Yes, but only highest 2000 minus whoever does not opt -in Yes, limited matches for free, more with subscription (Tier 1)
Download DNA Segment Match Spreadsheet Yes Yes No, must use DNAGedcom for any download, and no chromosome segment information Yes Tier 1 required, can only download 1000 through visualization options
Segment Spreadsheet Benefits View all matches and sort by segment, target all people who match on specific segments for chromosome browser View all matches and sort by segment, target all people who match on specific segments for chromosome browser No segment information but matches might transfer elsewhere where segment information is available View up to 2000 matches if matches have opted in. If you have initiated contact with a match, they will not drop off match list. Can download highest 1000 matches, target people who match on specific segments
Spreadsheet Challenges Includes small segments, I delete less than 7cM segments before using No X chromosome included No spreadsheet and no segment information Maximum of 2000 matches, minus those not opted in Download limited to 1000 with Tier 1, download not available without subscription
Chromosome Segment Information Yes Yes No, only total and longest segment, no segment address Yes Yes
Chromosome Browser Yes, requires $19 unlock if transfer Yes, requires $29 unlock or subscription if transfer No Yes Yes, some features require Tier 1 subscription
X Chromosome Included Yes No No Yes Yes, separate
Chromosome Browser Benefit Visual view of 7 or fewer matches Visual view of 7 or fewer matches, triangulation included if ALL people match on same portion of common segment No browser Visual view of 5 or fewer matches Unlimited view of matches, multiple options through comparison tools
Chromosome Browser Challenges Can’t tell whether maternal or paternal matches without additional info if don’t select bucketed matches Can’t tell whether maternal or paternal without additional info if don’t triangulate or you don’t know your common ancestor with at least one person in triangulation group No browser Can’t tell whether maternal or paternal without other information Can’t tell whether maternal or paternal without other information
Shared “In Common With” Matches Yes Yes Yes Yes, if everyone opts in Yes
Triangulation Yes, Phased Family Matching, plus chromosome browser Yes, included in chromosome browser if all people being compared match on that segment No, and no browser Yes, but only for 3 people if “Shared DNA” = Yes on Relatives in Common Yes, through multiple comparison tools
Ability to Know if Matches Match Each Other (also see autoclusters) Yes, through Matrix tool or if match on common bucketed segment through Family Matching Yes, through triangulation tool if all match on common segment No Yes, can compare any person to any other person on your match list Yes, through comparison tool selections
Autoclusters Can select up to 10 people for Matrix grid, also available for entire match list through Genetic Affairs and DNAGedcom which work well Genetic Affairs clustering included free, DNAGedcom has difficulty due to timeouts No, but Genetic Affairs and DNAGedcom work well No, but Genetic Affairs and DNAGedcom work well Yes, Genetic Affairs included in Tier 1 for selected kits, DNAGedcom is in beta
Trees Can upload or create tree. Linking you and relatives who match to tree triggers Phased Family Matching Can upload or create tree. Link yourself and kits you manage assists Theories of Family Relativity Can upload or create tree. Link your DNA to your tree to generate ThruLines. Recent new feature allows linking of DNA matches to tree. No tree support but can provide a link to a tree elsewhere Upload your tree so your matches can view
Matching and Automated Tree Construction of DNA Matches who Share Common Ancestors with You Genetic Affairs for matches with common ancestors with you Not available Genetic Affairs for matches with common ancestors with you No tree support Not available
Matching and Automated Tree Construction for DNA Matches with Common Ancestors with Each Other, But Not With You Genetic Affairs for matches with common ancestors with each other, but not with you Not available Genetic Affairs for matches with common ancestors with each other, but not with you No tree support Not available
DNAPainter Segment Compilation and Painting Yes, bucketed Family Match file can be uploaded which benefits tester immensely. Will be able to paint ethnicity segments soon. Yes No segment info available, encourage your matches to upload elsewhere Yes, and can paint ethnicity segments from 23andMe, Yes, but only for individually copied matches or highest 1000.
Y DNA and Mitochondrial Matching Yes, both, includes multiple tools, deep testing and detailed matching No No No, base haplogroup only, no matching No, haplogroup only if field manually completed by tester when uploading autosomal DNA file

Transfer Your DNA

Transferring your DNA results to each vendor who supports segment information and accepts transfers is not only important, it’s also a great way to extend your testing collar. Every vendor has strengths along with people who are found there and in no other database.

Ancestry does not provide segment information nor a chromosome browser, nor accept uploads, but you have several options to transfer your DNA file for free to other vendors who offer tools.

23andMe does provide a chromosome browser but does not accept uploads. You can download your DNA file and transfer free to other vendors.

I wrote detailed upload/download and transfer instructions for each vendor, here.

Two vendors and one third party support transfers into their systems. The transfers include matching. Basic tools are free, but all vendors charge a minimal fee for unlocking advanced tools, which is significantly less expensive than retesting:

Third-party tools that work with your DNA results include:

All vendors provide different tools and have unique strengths. Be sure that your DNA is working as hard as possible for you by fishing in every pond and utilizing third party tools to their highest potential.

Resource Articles

Explanations and step by step explanations of what you will see and what to do, when you open your DNA results for the first time.

Original article about chromosomes having 2 sides and how they affect genetic genealogy.

This article explains what triangulation is for autosomal DNA.

Why some matches may not be valid, and how to tell the difference.

This article explains the difference between a match group, meaning a group of people who match you, and triangulation, where that group also matches each other. The concepts are sound, but this article relies heavily on spreadsheets, before autocluster tools were available.

Parental phasing means assigning segment matches to either your paternal or maternal side.

Updated, introductory article about triangulation, providing the foundation for a series of articles about how to utilize triangulation at each vendor (FamilyTreeDNA, MyHeritage, 23andMe, GEDmatch, DNAPainter) that supports triangulation.

These articles step you through triangulation at each vendor.

DNAPainter facilitates painting maternally and paternally phased, bucketed matches from FamilyTreeDNA, a method of triangulation.

Compiled articles with instructions and ideas for using DNAPainter.

Autoclustering tool instructions.

How and why The Leeds Method works.

Step by step instructions for when and how to use FamilyTreeDNA’s chromosome browser.

Close family members are the key to verifying matches and identifying common ancestors.

This article details how much DNA specific relationships between people can expect to share.

Overview of transfer information and links to instruction articles for each vendor, below.

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Disclosure

I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

DNA Purchases and Free Transfers

Genealogy Products and Services

Genealogy Research

Fun DNA Stuff

  • Celebrate DNA – customized DNA themed t-shirts, bags, and other items

DNAPainter: Painting “Bucketed” Family Tree DNA Maternal and Paternal Family Finder Matches in One Fell Swoop

DNAPainter has done it again, providing genealogists with a wonderful tool that facilitates separating your matches into maternal and paternal categories so that they can be painted on the proper chromosome – in one fell swoop no less.

Of course, the entire purpose of painting your chromosomes is to identify segments that descend from specific ancestors in order to push those lines back further in time genealogically. Identifying segments, confirming and breaking down brick walls is the name of the game.

DNA Painter New Import Tool

The new DNAPainter tool relies on Family Tree DNA’s Phased Family Matching which assigns your matches to maternal and paternal buckets. On your match list, at the top, you’ll see the following which indicates how many matches you have in total and how many people are assigned to each bucket.

DNAPainter FF import.png

Note that these are individual matches, not total matching segments – that number would be higher.

In order for Family Tree DNA to create bucketed matches for you, you’ll need to:

  • Either create a tree or upload a GEDCOM file
  • Attach your DNA kit to “you” in your tree
  • Attach all 4th cousins and closer with whom you match to their proper location on your tree

Yes, it appears that Family Tree DNA is now using 4th cousins, not just third cousins and closer, which provides for additional bucketed matches.

How reliable is bucketing?

Quite. Occasionally one of two issues arise which becomes evident if you actually compare the matches’ segments to the parent with whom they are bucketed:

  • One or more of your matches’ segments do match you and your parent, but additionally, one or more segments match you, but not your parent
  • The X chromosome is particularly susceptible to this issue, especially with lower cM matches
  • Occasionally, a match that is large enough to be bucketed isn’t, likely because no known, linked cousin shares that segment

Getting Started

Get started by creating or uploading your tree at Family Tree DNA.

DNAPainter mytree.png

After uploading your GEDCOM file or creating your tree at Family Tree DNA, click on the “matches” icon at the top of the tree to link yourself and your relatives to their proper places on your tree. Your matches will show in the box below the helix icon.

DNAPainter FF matches.png

I created an example “twin” for myself to use for teaching purposes by uploading a file from Ancestry, so I’m going to attach that person to my tree as my “Evil Twin.” (Under normal circumstances, I do not recommend uploading duplicate files of anyone.)

DNAPainter FF matches link.png

Just drag and drop the person on your match list on top of their place on the tree.

DNAPainter Ff sister.png

Here I am as my sister, Example Adoptee.

I’ve wished for a very, very long time that there was a way to obtain a list of segment matches sorted by maternal and paternal bucket without having to perform spreadsheet gymnastics, and now there is, at DNAPainter.

DNAPainter does the heavy-lifting so you don’t have to.

What Does DNAPainter Do with Bucketed Matches?

When you are finished uploading two files at DNAPainter, you’ll have:

  • Maternal groups of triangulated matches
  • Paternal groups of triangulated matches
  • Matches that could not be assigned based on the bucketing. Some (but not all) of these matches will be identical by chance – typically roughly 15-20% of your match list. You can read about identical by chance, here.

I’ll walk you through the painting process step by step.

First, you need to be sure your relatives are connected to your tree at Family Tree DNA so that you have matches assigned to your maternal and paternal buckets. The more relatives you connect, per the instructions in the previous section, the more matching people will be able to be placed into maternal or paternal buckets.

Painting Bucketed Matches at DNAPainter

I wrote basic articles about how to use DNAPainter here. If you’re unfamiliar with how to use DNAPainter or it’s new to you, now would be a good time to read those articles. This next section assumes that you’re using DNAPainter. If not, go ahead, register, and set up a profile. One profile is free for everyone, but multiple profiles require a subscription.

First, make a duplicate of the profile that you’re working with. This DNAPainter upload tool is in beta.

DNAPainter duplicate profile.png

Since I’m teaching and experimenting, I am using a fresh, new profile for this experiment. If it works successfully, I’ll duplicate my working profile, just in case something goes wrong or doesn’t generate the results I expect, and repeat these steps there.

Second, at Family Tree DNA, Download a fresh copy of your complete matching segment file. This “Download Segments” link is found at the top right of the chromosome browser page.

DNAPainter ff download segments.png

Third, download your matches at the bottom left of the actual matches page. This file hold information about your matches, such as which ones are bucketed, but no segment information. That’s in the other file.

DNAPainter csv.png

Name both of these files something you can easily identify and that tells them apart. I called the first one “Segments” in front of the file name and the second one “Matches” in front of the file name.

Fourth, at DNAPainter, you’ll need to import your entire downloaded segment file that you just downloaded from Family Tree DNA. I exclude segments under 7cM because they are about 50% identical by chance.

DNAPainter import instructions

click to enlarge

Select the segment file you just named and click on import.

DNAPainter both.png

At this point, your chromosomes at DNAPainter will look like this, assuming you’re using a new profile with nothing else painted.

Let’s expand chromosome 1 and see what it looks like.

DNAPainter chr 1 both.png

Note that all segments are painted over both chromosomes, meaning both the maternal and paternal copies of chromosome 1, partially shown above, because at this point, DNAPainter can’t tell which people match on the maternal and which people match on the paternal sides. The second “matches” file from Family Tree DNA has not yet been imported into DNAPainter, which tells DNAPainter which matches are on the maternal and which are on the paternal chromosomes.

If you’re not workign with a new profile, then you’ll also see the segments you’ve already painted. DNAPainter attempts to NOT paint segments that appear to have previously been painted.

Fifth, at DNAPainter, click on the “Import mat/pat info from ftDNA” link on the left which will provide you with a page to import the matches file information. This is the file that has maternal and paternal sides specified for bucketed matches. DNAPainter needs both the segment file, which you already imported, and the matches file.

DNAPainter import bucket

click to enlarge

After the second import, the “matches” file, my matches are magically redistributed onto their appropriate chromosomes based on the maternal and paternal bucketing information.

I love this tool!

At this point, you will have three groups of matches, assuming you have people assigned to your maternal and paternal buckets.

  • A “Shared” group for people who are related to both of your parents, or who aren’t designated as a bucketed match to either parent
  • Maternal group (pink chromosome)
  • Paternal group (blue chromosome)

It’s Soup!!!

I’m so excited. Now my matches are divided into maternal and paternal chromosome groups.

DNAPainter import complete.png

Just so you know, I changed the colors of my legend at DNAPainter using “edit group,” because all three groups were shades of pink after the import and I wanted to be able to see the difference clearly.

DNAPainter legend.png

Your Painted Chromosomes

Let’s take a look at what we have.

DNAPainter both, mat, pat.png

There’s still pink showing, meaning undetermined, which gets painted over both the maternal and paternal chromosomes, but there’s also a lot of magenta (maternal) and blue (paternal) showing now too as a result of bucketing.

Let’s look at chromosome 1.

DNAPainter chr 1 all.png

This detail, which is actually a summary, shows that the bucketed maternal (magenta) and paternal (blue) matches have actually covered most of the chromosome. There are still a few areas without coverage, but not many.

For a genealogist, this is beautiful!!!

How many matches were painted?

DNAPainter paternal total.png

DNAPainter maternal total.png

Expanding chromosome 1, and scrolling to the maternal portion, I can now see that I have several painted maternal segments, and almost the entire chromosome is covered.

Here’s the exciting part!

DNAPainter ch1 1 mat expanded.png

I stared the relatives I know, on the painting, above and on the pedigree chart, below. The green group descends through Hiram Ferverda and Eva Miller, the yellow group through Antoine Lore and Rachel Hill. The blue group is Acadian, upstream of Antoine Lore.

DNAPainter maternal pedigree.png

Those ancestors are shown by star color on my pedigree chart.

I can now focus on the genealogies of the other unstarred people to see if their genealogy can push those segments back further in time to older ancestors.

On my Dad’s side, the first part of chromosome 1 is equally as exciting.

DNAPainter chr 1 pat expanded.png

The yellow star only pushed this triangulated group back only to my grandparents, but the green star is from a cousin descended from my great-grandparents. The red star matches are even more exciting, because my common ancestor with Lawson is my brick wall – Marcus Younger and his wife, Susanna, surname unknown, parents of Mary Younger.

DNAPainter paternal pedigree.png

I need to really focus hard on this cluster of 12 people because THEIR common ancestors in their trees may well provide the key I need to push back another generation – through the brick wall. That is, after all, the goal of genetic genealogy.

Woohoooo!

Manual Spreadsheet Compare

Because I decided to torture myself one mid-winter day, and night, I wanted to see how much difference there is between the bucketed matches that I just painted and actual matches that I’ve identified by downloading my parents’ segment match files and mine and comparing them manually against each other. I removed any matches in my file that were not matches to my parent, in addition to me, then painted the rest.

I’ll import the resulting manual spreadsheet into the same experimental DNAPainter profile so we can view matches that were NOT painted previously. DNAPainter does not paint matches previously painted, if it can tell the difference. Since both of these files are from downloads, without the name of the matches being in any way modified, DNAPainter should be able to recognize everyone and only paint new segment matches.

Please note here that the PERSON unquestionably belongs bucketed to the parental side in question, but not all SEGMENTS necessarily match you and your parent. Some will not, and those are the segments that I removed from my spreadsheet.

DNAPainter manual spreadsheet example.png

Here’s a made-up example where I’ve combined my matches and my mother’s matches in one spreadsheet in order to facilitate this comparison. I colored my Mom’s matches green so they are easy to see when comparing to my own, then sorting by the match name.

Person 1 matches me and Mom both, at 10 cM on chromosome 1. Person 1 is assigned to my maternal side due to the matches above 9 cM, the lowest threshold at Family Tree DNA for bucketing.

In this example, we can see that Person 1 matches me and Mom (colored green), both, on the segment on chromosome 1. That match, bracketed by red, is a valid, phased, match and should be painted.

However, Person 1 also matches me, but NOT Mom on chromosome 2. Because Person 1 is bucketed to mother, this segment on chromosome 2 will also be painted to my maternal chromosome 2 using the DNAPainter import. The only way to sort this out is to do the comparison manually.

The same holds true for the X match shown. The two segments shown in red should NOT be painted, but they will be unless you are willing to compare you and your parents’ matches manually, you will just have to evaluate segments individually when you see that you’re working in a cluster where matches have been assigned through the mass import tool.

If you choose to compare the spreadsheets manually to assure that you’re not painting segments like the red ones above, DNAPainter provides instructions for you to create your own mass upload template, which is what I did after removing any segment matches of people that were not “in common” between me and mother on the same chromosomal segment, like the red ones, above.

Please note that if you delete the erroneous segments and later reimport your bucketed matches, they will appear again. I’m more inclined to leave them, making a note.

I did not do a manual comparison of my father’s side of the tree after discovering just how little difference was found on my mother’s side, and how much effort was involved in the manual comparison.

Creating a Mass Upload Template and File

DNAPainter custom mass upload.png

The instructions for creating your own mass upload file are provided by DNAPainter – please follow them exactly.

In my case, after doing the manual spreadsheet compare with my mother, only a total of 18 new segments were imported that were not previously identified by bucketing.

Three of those segments were over 15cM, but the rest were smaller. I expected there would be more. Family Tree DNA is clearly doing a great job with maternal and paternal bucketing assignments, but they can’t do it without known relatives that have also tested and are linked to your tree. The very small discrepancy is likely due to matches with cousins that I have not been able to link on my tree.

The great news is that because DNAPainter recognizes already-painted segments, I can repeat this anytime and just paint the new segments, without worrying about duplicates.

  • The information above pertains to segments that should have been painted, but weren’t.
  • The information below pertains to segments that were painted, but should not have been.

I did not keep track of how many segments I deleted that would have erroneously been painted. There were certainly more than 18, but not an overwhelming number. Enough though to let me know to be careful and confirm the segment match individually before using any of the mass uploaded matches for hypothesis or conclusions.

Given that this experiment went well, I created a copy of my “real” profile in order to do the same import and see what discoveries are waiting!

Before and After

Before I did the imports into my “real” file (after making a copy, of course,) I had painted 82% of my DNA using 1700 segments. Of course, each one of those segments in my original profile is identified with an ancestor, even if they aren’t very far back in time.

Although I didn’t paint matches in common with my mother before this mass import, each of my matches in common with my mother are in common with one or the other of my maternal grandparents – and by using other known matches I can likely push the identity of those segments further back in time.

Status Percent Segments Painted
Before mass Phased Family Match bucketed import 82 1700
After mass Phased Family Match bucketed import 88 7123
After additional manual matches with my mother added 88 7141

While I did receive 18 additional matching segments by utilizing the manually intensive spreadsheet matching and removal process, I did not receive enough more matches to justify the hours and hours of work. I won’t be doing that anymore with Family Tree DNA files since they have so graciously provided bucketing and DNAPainter can leverage that functionality.

Those hours will be much better spent focusing on unraveling the ancestors whose stories are told in clusters of triangulated matches.

I Love The Import Tool, But It’s Not Perfect

Keep in mind that the X chromosome needs a match of approximately twice the size of a regular chromosome to be as reliable. In other words, a 14 cM threshold for the X chromosome is roughly equivalent to a 7 cM match for any other chromosome. Said another way, a 7 cM match on the X is about equal to a 3.5 cM match on any other chromosome.

X matches are not created equal.

The SNP density on the X chromosome is about half that of the other chromosomes, making it virtually impossible to use the same matching criteria. I don’t encourage using matches of less than 500 SNPs unless you know you’re in a triangulated group and WITH at least a few larger, proven matches on that segment of the X chromosome.

Having said that, X matches, due to their unique inheritance path can persist for many generations and be extremely useful. You can read about working with the X chromosome here and here.

I noticed when I was comparing segments in the manual spreadsheet that I had to remove many X matches with people who had identical matches on other chromosomes with me and my mother. In other words, just because they matched my mother and me exactly on one chromosome, that phasing did not, by default, extend to matching on other segments.

I checked my manually curated file and discovered that I had a total of seven X matches that should have been, and were, painted because they matched me and Mom both.

DNAPainter X spreadsheet example.png

However, there were many that didn’t match me and Mom both, matching only me, that were painted because that person was bucketed (assigned) to my maternal side because a different segment phased to mother correctly.

On the X chromosome, here’s what happened.

DNAPainter maternal X.png

You can see that a lot more than 7 bright red matches were painted – 26 more to be exact. That’s because if an individual is bucketed on your maternal or paternal side, it’s presumed that all of the matching segments come from the same ancestor and are legitimate, meaning identical by descent and not by chance. They aren’t. Every single segment has an inheritance path and story of its own – and just because one segment triangulates does NOT mean that other segments that match that person will triangulate as well.

The X chromosome is the worst case scenario of course, because these 7 cM segments are actually as reliable as roughly 3.5 cM segments on any other chromosome, which is to say that more than 50% of them will be incorrect. However, some will be accurate and those will match me and mother both. 21% of the X matches to people who phased and triangulated on other chromosomes were accurate – 79% were not. Thankfully, we have phasing, bucketing and tools like this to be able to tell the difference so we can utilize the 21% that are accurate. No one wants to throw the baby out with the bath water, nor do we want to chase after phantoms.

Keep in mind that Phased Family Matching, like any other tool, is just that, a tool and needs some level of critical analysis.

Every Segment Has Its Own Story

We know that every single DNA segment has an independent inheritance path and story of its own. (Yes, I’ve said that several time now because it’s critically important so that you don’t wind up barking up the wrong tree, literally, pardon the pun.)

In the graphic above of my painted X chromosome matches, only the six matches with green stars are on the hand-curated match list. One had already been painted previously. The balance of the bright red matches were a part of the mass import and need to be deleted. Additionally, one of the accurate matches did not upload for some reason, so I’ll add that one manually.

I suggest that you go ahead and paint your bucketed segments, but understand that you may have a red herring or two in your crop of painted segment matches.

As you begin to work with these clusters of matches, check your matching segments with your parents (or other family members who were used in bucketing) and make sure that all the segments that have been painted by bulk upload actually match on all of the same segments.

If you have a parent that tested, there is no need to see if you and your match match other relatives on that same side. If your match does not match you and your parent on some significant overlapping portion of that same segment, the match is invalid. DNA does not “skip generations.”

If you don’t have a parent that has tested, your known relatives are your salvation, and the key to bucketed matches.

The great news is that you can easily see that a bulk match was painted from the coloring of the batch import. As you discover the relevant genealogy and confirm that all segments actually match your parent (or another family member, if you don’t have parents to test,) move the matching person to the appropriately colored ancestral group.

I further recommend that you hand curate the X chromosome using a spreadsheet. The nature of the X makes depending on phased matching too risky, especially with a tool like DNAPainter that can’t differentiate between a legitimate and non-legitimate match. The X chromosome matches are extraordinarily valuable because they can be useful in ways that other chromosomes can’t be due to the X’s unique inheritance path.

What About You?

If you don’t have your DNA at Family Tree DNA and you have tested elsewhere, you can transfer your DNA file for free, allowing you to see your matches and use many of the Family Tree DNA tools. However, to access the chromosome browser, which you’ll need for DNA painting, you’ll need to purchase the unlock for $19, but that’s still a lot less than retesting.

Here are transfer instructions for transferring your DNA file from 23andMe, Ancestry or MyHeritage.

If you have not purchased a Family Finder test at Family Tree DNA and don’t have a DNA file to transfer, you can order a test here.

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Disclosure

I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

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Hit a Genetic Genealogy Home Run Using Your Double-Sided Two-Faced Chromosomes While Avoiding Imposters

Do you want to hit a home run with your DNA test, but find yourself a mite bewildered?

Yep, those matches can be somewhat confusing – especially if you don’t understand what’s going on. Do you have a nagging feeling that you might be missing something?

I’m going to explain chromosome matching, and its big sister, triangulation, step by step to remove any confusion, to help you sort through your matches and avoid imposters.

This article is one of the most challenging I’ve ever written – in part because it’s a concept that I’m so familiar with but can be, and is, misinterpreted so easily. I see mistakes and confusion daily, which means that resulting conclusions stand a good chance of being wrong.

I’ve tried to simplify these concepts by giving you easy-to-use memory tools.

There are three key phrases to remember, as memory-joggers when you work through your matches using a chromosome browser: double-sided, two faces and imposter. While these are “cute,” they are also quite useful.

When you’re having a confusing moment, think back to these memory-jogging key words and walk yourself through your matches using these steps.

These three concepts are the foundation of understanding your matches, accurately, as they pertain to your genealogy. Please feel free to share, link or forward this article to your friends and especially your family members (including distant cousins) who work with genetic genealogy. 

Now, it’s time to enjoy your double-sided, two-faced chromosomes and avoid those imposters:)

Are you ready? Grab a nice cup of coffee or tea and learn how to hit home runs!

Double-Sided – Yes, Really

Your chromosomes really are double sided, and two-faced too – and that’s a good thing!

However, it’s initially confusing because when we view our matches in a chromosome browser, it looks like we only have one “bar” or chromosome and our matches from both our maternal and paternal sides are both shown on our one single bar.

How can this be? We all have two copies of chromosome 1, one from each parent.

Chromosome 1 match.png

This is my chromosome 1, with my match showing in blue when compared to my chromosome, in gray, as the background.

However, I don’t know if this blue person matches me on my mother’s or father’s chromosome 1, both of which I inherited. It could be either. Or neither – meaning the dreaded imposter – especially that small blue piece at left.

What you’re seeing above is in essence both “sides” of my chromosome number 1, blended together, in one bar. That’s what I mean by double-sided.

There’s no way to tell which side or match is maternal and which is paternal without additional information – and misunderstanding leads to misinterpreting results.

Let’s straighten this out and talk about what matches do and don’t mean – and why they can be perplexing. Oh, and how to discover those imposters!

Your Three Matches

Let’s say you have three matches.

At Family Tree DNA, the example chromosome browser I’m using, or at any vendor with a chromosome browser, you select your matches which are viewed against your chromosomes. Your chromosomes are always the background, meaning in this case, the grey background.

Chromosome 1-4.png

  • This is NOT three copies each of your chromosomes 1, 2, 3 and 4.
  • This is NOT displaying your maternal and paternal copies of each chromosome pictured.
  • We CANNOT tell anything from this image alone relative to maternal and paternal side matches.
  • This IS showing three individual people matching you on your chromosome 1 and the same three people matching you in the same order on every chromosome in the picture.

Let’s look at what this means and why we want to utilize a chromosome browser.

I selected three matches that I know are not all related through the same parent so I can demonstrate how confusing matches can be sorted out. Throughout this article, I’ve tried to explain each concept in at least two ways.

Please note that I’m using only chromsomes 1-4 as examples, not because they are any more, or less, important than the other chromosomes, but because showing all 22 would not add any benefit to the discussion. The X chromosome has a separate inheritance path and I wrote about that here.

Let’s start with a basic question.

Why Would I Want to Use a Chromosome Browser?

Genealogists view matches on chromosome browsers because:

  • We want to see where our matches match us on our chromosomes
  • We’d like to identify our common ancestor with our match
  • We want to assign a matching segment to a specific ancestor or ancestral line, which confirmed those ancestors as ours
  • When multiple people match us on the same location on the chromosome browser, that’s a hint telling us that we need to scrutinize those matches more closely to determine if those people match us on our maternal or paternal side which is the first step in assigning that segment to an ancestor

Once we accurately assign a segment to an ancestor, when anyone else matches us (and those other people) on that same segment, we know which ancestral line they match through – which is a great head start in terms of identifying our common ancestor with our new match.

That’s a genetic genealogy home run!

Home Runs 

There are four bases in a genetic genealogy home run.

  1. Determine whether you actually match someone on the same segment
  2. Which is the first step in determining that you match a group of people on the same segment
  3. And that you descend from a common ancestor
  4. The fourth step, or the home run, is to determine which ancestor you have in common, assigning that segment to that ancestor

If you can’t see segment information, you can’t use a chromosome browser and you can’t confirm the match on that segment, nor can you assign that segment to a particular ancestor, or ancestral couple.

The entire purpose of genealogy is to identify and confirm ancestors. Genetic genealogy confirms the paper trail and breaks down even more brick walls.

But before you can do that, you have to understand what matches mean and how to use them.

The first step is to understand that our chromosomes are double-sided and you can’ t see both of your chromosomes at once!

Double Sided – You Can’t See Both of Your Chromosomes at Once

The confusing part of the chromosome browser is that it can only “see” your two chromosomes blended as one. They are both there, but you just can’t see them separately.

Here’s the important concept:

You have 2 copies of chromosomes 1 through 22 – one copy that you received from your mother and one from your father, but you can’t “see” them separately.

When your DNA is sequenced, your DNA from your parents’ chromosomes emerges as if it has been through a blender. Your mother’s chromosome 1 and your father’s chromosome 1 are blended together. That means that without additional information, the vendor can’t tell which matches are from your father’s side and which are from your mother’s side – and neither can you.

All the vendor can tell is that someone matches you on the blended version of your parents. This isn’t a negative reflection on the vendors, it’s just how the science works.

Chromosome 1.png

Applying this to chromosome 1, above, means that each segment from each person, the blue person, the red person and the teal person might match you on either one of your chromosomes – the paternal chromosome or the maternal chromosome – but because the DNA of your mother and father are blended – there’s no way without additional information to sort your chromosome 1 into a maternal and paternal “side.”

Hence, you’re viewing “one” copy of your combined chromosomes above, but it’s actually “two-sided” with both maternal and paternal matches displayed in the chromosome browser.

Parent-Child Matches

Let’s explain this another way.

Chromosome parent.png

The example above shows one of my parents matching me. Don’t be deceived by the color blue which is selected randomly. It could be either parent. We don’t know.

You can see that I match my parent on the entire length of chromosome 1, but there is no way for me to tell if I’m looking at my mother’s match or my father’s match, because both of my parents (and my children) will match me on exactly the same locations (all of them) on my chromosome 1.

Chromosome parent child.png

In fact, here is a combination of my children and my parents matching me on my chromosome 1.

To sort out who is matching on paternal and maternal chromosomes, or the double sides, I need more information. Let’s look at how inheritance works.

Stay with me!

Inheritance Example

Let’s take a look at how inheritance works visually, using an example segment on chromosome 1.

Chromosome inheritance.png

In the example above:

  • The first column shows addresses 1-10 on chromosome 1. In this illustration, we are only looking at positions, chromosome locations or addresses 1-10, but real chromosomes have tens of thousands of addresses. Think of your chromosome as a street with the same house numbers on both sides. One side is Mom’s and one side is Dad’s, but you can’t tell which is which by looking at the house numbers because the house numbers are identical on both sides of the street.
  • The DNA pieces, or nucleotides (T, A, C or G,) that you received from your Mom are shown in the column labeled Mom #1, meaning we’re looking at your mother’s pink chromosome #1 at addresses 1-10. In our example she has all As that live on her side of the street at addresses 1-10.
  • The DNA pieces that you received from your Dad are shown in the blue column and are all Cs living on his side of the street in locations 1-10.

In other words, the values that live in the Mom and Dad locations on your chromosome streets are different. Two different faces.

However, all that the laboratory equipment can see is that there are two values at address 1, A and C, in no particular order. The lab can’t tell which nucleotide came from which parent or which side of the street they live on.

The DNA sequencer knows that it found two values at each address, meaning that there are two DNA strands, but the output is jumbled, as shown in the First and Second read columns. The machine knows that you have an A and C at the first address, and a C and A at the second address, but it can’t put the sequence of all As together and the sequence of all Cs together. What the sequencer sees is entirely unordered.

This happens because your maternal and paternal DNA is mixed together during the extraction process.

Chromosome actual

Click to enlarge image.

Looking at the portion of chromosome 1 where the blue and teal people both match you – your actual blended values are shown overlayed on that segment, above. We don’t know why the blue and the teal people are matching you. They could be matching because they have all As (maternal), all Cs (paternal) or some combination of As and Cs (a false positive match that is identical by chance.)

There are only two ways to reassemble your nucleotides (T, A, C, and G) in order and then to identify the sides as maternal and paternal – phasing and matching.

As you read this next section, it does NOT mean that you must have a parent for a chromosome browser to be useful – but it does mean you need to understand these concepts.

There are two types of phasing.

Parental Phasing

  • Parental Phasing is when your DNA is compared against that of one or both parents and sorted based on that comparison.

Chromosome inheritance actual.png

Parental phasing requires that at least one parent’s DNA is available, has been sequenced and is available for matching.

In our example, Dad’s first 10 locations (that you inherited) on chromosome 1 are shown, at left, with your two values shown as the first and second reads. One of your read values came from your father and the other one came from your mother. In this case, the Cs came from your father. (I’m using A and C as examples, but the values could just as easily be T or G or any combination.)

When parental phasing occurs, the DNA of one of your parents is compared to yours. In this case, your Dad gave you a C in locations 1-10.

Now, the vendor can look at your DNA and assign your DNA to one parent or the other. There can be some complicating factors, like if both your parents have the same nucleotides, but let’s keep our example simple.

In our example above, you can see that I’ve colored portions of the first and second strands blue to represent that the C value at that address can be assigned through parental phasing to your father.

Conversely, because your mother’s DNA is NOT available in our example, we can’t compare your DNA to hers, but all is not lost. Because we know which nucleotides came from your father, the remaining nucleotides had to come from your mother. Hence, the As remain after the Cs are assigned to your father and belong to your mother. These remaining nucleotides can logically be recombined into your mother’s DNA – because we’ve subtracted Dad’s DNA.

I’ve reassembled Mom, in pink, at right.

Statistical/Academic Phasing

  • A second type of phasing uses something referred to as statistical or academic phasing.

Statistical phasing is less successful because it uses statistical calculations based on reference populations. In other words, it uses a “most likely” scenario.

By studying reference populations, we know scientifically that, generally, for our example addresses 1-10, we either see all As or all Cs grouped together.

Based on this knowledge, the Cs can then logically be grouped together on one “side” and As grouped together on the other “side,” but we still have no way to know which side is maternal or paternal for you. We only know that normally, in a specific population, we see all As or all Cs. After assigning strings or groups of nucleotides together, the algorithm then attempts to see which groups are found together, thereby assigning genetic “sides.” Assigning the wrong groups to the wrong side sometimes happens using statistical phasing and is called strand swap.

Once the DNA is assigned to physical “sides” without a parent or matching, we still can’t identify which side is paternal and which is maternal for you.

Statistical or academic phasing isn’t always accurate, in part because of the differences found in various reference populations and resulting admixture. Sometimes segments don’t match well with any population. As more people test and more reference populations become available, statistical/academic phasing improves. 23andMe uses academic phasing for ethnicity, resulting in a strand swap error for me. Ancestry uses academic phasing before matching.

By comparison to statistical or academic phasing, parental phasing with either or both parents is highly accurate which is why we test our parents and grandparents whenever possible. Even if the vendor doesn’t use our parents’ results, we certainly can!

If someone matches you and your parent too, you know that match is from that parent’s side of your tree.

Matching

The second methodology to sort your DNA into maternal and paternal sides is matching, either with or without your parents.

Matching to multiple known relatives on specific segments assigns those segments of your DNA to the common ancestor of those individuals.

In other words, when I match my first cousin, and our genealogy indicates that we share grandparents – assuming we match on the appropriate amount of DNA for the expected relationship – that match goes a long way to confirming our common ancestor(s).

The closer the relationship, the more comfortable we can be with the confirmation. For example, if you match someone at a parental level, they must be either your biological mother, father or child.

While parent, sibling and close relationships are relatively obvious, more distant relationships are not and can occur though unknown or multiple ancestors. In those cases, we need multiple matches through different children of that ancestor to reasonably confirm ancestral descent.

Ok, but how do we do that? Let’s start with some basics that can be confusing.

What are we really seeing when we look at a chromosome browser?

The Grey/Opaque Background is Your Chromosome

It’s important to realize that you will see as many images of your chromosome(s) as people you have selected to match against.

This means that if you’ve selected 3 people to match against your chromosomes, then you’ll see three images of your chromosome 1, three images of your chromosome 2, three images of your chromosome 3, three images of your chromosome 4, and so forth.

Remember, chromosomes are double-sided, so you don’t know whether these are maternal or paternal matches (or imposters.)

In the illustration below, I’ve selected three people to match against my chromosomes in the chromosome browser. One person is shown as a blue match, one as a red match, and one as a teal match. Where these three people match me on each chromosome is shown by the colored segments on the three separate images.

Chromosome 1.png

My chromosome 1 is shown above. These images are simply three people matching to my chromosome 1, stacked on top of each other, like cordwood.

The first image is for the blue person. The second image is for the red person. The third image is for the teal person.

If I selected another person, they would be assigned a different color (by the system) and a fourth stacked image would occur.

These stacked images of your chromosomes are NOT inherently maternal or paternal.

In other words, the blue person could match me maternally and the red person paternally, or any combination of maternal and paternal. Colors are not relevant – in other words colors are system assigned randomly.

Notice that portions of the blue and teal matches overlap at some of the same locations/addresses, which is immediately visible when using a chromosome browser. These areas of common matching are of particular interest.

Let’s look closer at how chromosome browser matching works.

What about those colorful bars?

Chromosome Browser Matching

When you look at your chromosome browser matches, you may see colored bars on several chromosomes. In the display for each chromosome, the same color will always be shown in the same order. Most people, unless very close relatives, won’t match you on every chromosome.

Below, we’re looking at three individuals matching on my chromosomes 1, 2, 3 and 4.

Chromosome browser.png

The blue person will be shown in location A on every chromosome at the top. You can see that the blue person does not match me on chromosome 2 but does match me on chromosomes 1, 3 and 4.

The red person will always be shown in the second position, B, on each chromosome. The red person does not match me on chromosomes 2 or 4.

The aqua person will always be shown in position C on each chromosome. The aqua person matches me on at least a small segment of chromosomes 1-4.

When you close the browser and select different people to match, the colors will change and the stacking order perhaps, but each person selected will always be consistently displayed in the same position on all of your chromosomes each time you view.

The Same Address – Stacked Matches

In the example above, we can see that several locations show stacked segments in the same location on the browser.

Chromosome browser locations.png

This means that on chromosome 1, the blue and green person both match me on at least part of the same addresses – the areas that overlap fully. Remember, we don’t know if that means the maternal side or the paternal side of the street. Each match could match on the same or different sides.

Said another way, blue could be maternal and teal could be paternal (or vice versa,) or both could be maternal or paternal. One or the other or both could be imposters, although with large segments that’s very unlikely.

On chromosome 4, blue and teal both match me on two common locations, but the teal person extends beyond the length of the matching blue segments.

Chromosome 3 is different because all three people match me at the same address. Even though the red and teal matching segments are longer, the shared portion of the segment between all three people, the length of the blue segment, is significant.

The fact that the stacked matches are in the same places on the chromosomes, directly above/below each other, DOES NOT mean the matches also match each other.

The only way to know whether these matches are both on one side of my tree is whether or not they match each other. Do they look the same or different? One face or two? We can’t tell from this view alone.

We need to evaluate!

Two Faces – Matching Can be Deceptive!

What do these matches mean? Let’s ask and answer a few questions.

  • Does a stacked match mean that one of these people match on my mother’s side and one on my father’s side?

They might, but stacked matches don’t MEAN that.

If one match is maternal, and one is paternal, they still appear at the same location on your chromosome browser because Mom and Dad each have a side of the street, meaning a chromosome that you inherited.

Remember in our example that even though they have the same street address, Dad has blue Cs and Mom has pink As living at that location. In other words, their faces look different. So unless Mom and Dad have the same DNA on that entire segment of addresses, 1-10, Mom and Dad won’t match each other.

Therefore, my maternal and paternal matches won’t match each other either on that segment either, unless:

  1. They are related to me through both of my parents and on that specific location.
  2. My mother and father are related to each other and their DNA is the same on that segment.
  3. There is significant endogamy that causes my parents to share DNA segments from their more distant ancestors, even though they are not related in the past few generations.
  4. The segments are small (segments less than 7cM are false matches roughly 50% of the time) and therefore the match is simply identical by chance. I wrote about that here. The chart showing valid cM match percentages is shown here, but to summarize, 7-8 cMs are valid roughly 46% of the time, 8-9 cM roughly 66%, 9-10 cM roughly 91%, 10-11 cM roughly 95, but 100 is not reached until about 20 cM and I have seen a few exceptions above that, especially when imputation is involved.

Chromosome inheritance match.png

In this inheritance example, we see that pink Match #1 is from Mom’s side and matches the DNA I inherited from pink Mom. Blue Match #2 is from Dad’s side and matches the DNA I inherited from blue Dad. But as you can see, Match #1 and Match #2 do not match each other.

Therefore, the address is only half the story (double-sided.)

What lives at the address is the other half. Mom and Dad have two separate faces!

Chromosome actual overlay

Click to enlarge image

Looking at our example of what our DNA in parental order really looks like on chromosome 1, we see that the blue person actually matches on my maternal side with all As, and the teal person on the paternal side with all Cs.

  • Does a stacked match on the chromosome browser mean that two people match each other?

Sometimes it happens, but not necessarily, as shown in our example above. The blue and teal person would not match each other. Remember, addresses (the street is double-sided) but the nucleotides that live at that address tell the real story. Think two different looking faces, Mom’s and Dad’s, peering out those windows.

If stacked matches match each other too – then they match me on the same parental side. If they don’t match each other, don’t be deceived just because they live at the same address. Remember – Mom’s and Dad’s two faces look different.

For example, if both the blue and teal person match me maternally, with all As, they would also match each other. The addresses match and the values that live at the address match too. They look exactly the same – so they both match me on either my maternal or paternal side – but it’s up to me to figure out which is which using genealogy.

Chromosome actual maternal.png

Click to enlarge image

When my matches do match each other on this segment, plus match me of course, it’s called triangulation.

Triangulation – Think of 3

If my two matches match each other on this segment, in addition to me, it’s called triangulation which is genealogically significant, assuming:

  1. That the triangulated people are not closely related. Triangulation with two siblings, for example, isn’t terribly significant because the common ancestor is only their parents. Same situation with a child and a parent.
  2. The triangulated segments are not small. Triangulation, like matching, on small segments can happen by chance.
  3. Enough people triangulate on the same segment that descends from a common ancestor to confirm the validity of the common ancestor’s identity, also confirming that the match is identical by descent, not identical by chance.

Chromosome inheritance triangulation.png

The key to determining whether my two matches both match me on my maternal side (above) or paternal side is whether they also match each other.

If so, assuming all three of the conditions above are true, we triangulate.

Next, let’s look at a three-person match on the same segment and how to determine if they triangulate.

Three Way Matching and Identifying Imposters

Chromosome 3 in our example is slightly different, because all three people match me on at least a portion of that segment, meaning at the same address. The red and teal segments line up directly under the blue segment – so the portion that I can potentially match identically to all 3 people is the length of the blue segment. It’s easy to get excited, but don’t get excited quite yet.

Chromosome 3 way match.png

Given that three people match me on the same street address/location, one of the following three situations must be true:

  • Situation 1- All three people match each other in addition to me, on that same segment, which means that all three of them match me on either the maternal or paternal side. This confirms that we are related on the same side, but not how or which side.

Chromosome paternal.png

In order to determine which side, maternal or paternal, I need to look at their and my genealogy. The blue arrows in these examples mean that I’ve determined these matches to all be on my father’s side utilizing a combination of genealogy plus DNA matching. If your parent is alive, this part is easy. If not, you’ll need to utilize common matching and/or triangulation with known relatives.

  • Situation 2 – Of these three people, Cheryl, the blue bar on top, matches me but does not match the other two. Charlene and David, the red and teal, match each other, plus me, but not Cheryl.

Chromosome maternal paternal.png

This means that at least either my maternal or paternal side is represented, given that Charlene and David also match each other. Until I can look at the identity of who matches, or their genealogy, I can’t tell which person or people descend from which side.

In this case, I’ve determined that Cheryl, my first cousin, with the pink arrow matches me on Mom’s side and Charlene and David, with the blue arrows, match me on Dad’s side. So both my maternal and paternal sides are represented – my maternal side with the pink arrow as well as my father’s side with the blue arrows.

If Cheryl was a more distant match, I would need additional triangulated matches to family members to confirm her match as legitimate and not a false positive or identical by chance.

  • Situation 3 – Of the three people, all three match me at the same addresses, but none of the three people match each other. How is this even possible?

Chromosome identical by chance.png

This situation seems very counter-intuitive since I have only 2 chromosomes, one from Mom and one from Dad – 2 sidesof the street. It is confusing until you realize that one match (Cheryl and me, pink arrow) would be maternal, one would be paternal (Charlene and me, blue arrow) and the third (David and me, red arrows) would have DNA that bounces back and forth between my maternal and paternal sides, meaning the match with David is identical by chance (IBC.)

This means the third person, David, would match me, but not the people that are actually maternal and paternal matches. Let’s take a look at how this works

Chromosome maternal paternal IBC.png

The addresses are the same, but the values that live at the addresses are not in this third scenario.

Maternal pink Match #1 is Cheryl, paternal blue Match #2 is Charlene.

In this example, Match #3, David, matches me because he has pink and blue at the same addresses that Mom and Dad have pink and blue, but he doesn’t have all pink (Mom) nor all blue (Dad), so he does NOT match either Cheryl or Charlene. This means that he is not a valid genealogical match – but is instead what is known as a false positive – identical by chance, not by descent. In essence, a wily genetic imposter waiting to fool unwary genealogists!

In his case, David is literally “two-faced” with parts of both values that live in the maternal house and the paternal house at those addresses. He is a “two-faced imposter” because he has elements of both but isn’t either maternal or paternal.

This is the perfect example of why matching and triangulating to known and confirmed family members is critical.

All three people, Cheryl, Charlene and David match me (double sided chromosomes), but none of them match each other (two legitimate faces – one from each parent’s side plus one imposter that doesn’t match either the legitimate maternal or paternal relatives on that segment.)

Remember Three Things

  1. Double-Sided – Mom and Dad both have the same addresses on both sides of each chromosome street.
  2. Two Legitimate Faces – The DNA values, nucleotides, will have a unique pattern for both your Mom and Dad (unless they are endogamous or related) and therefore, there are two legitimate matching patterns on each chromsome – one for Mom and one for Dad. Two legitimate and different faces peering out of the houses on Mom’s side and Dad’s side of the street.
  3. Two-Faced Imposters – those identical by chance matches which zig-zag back and forth between Mom and Dad’s DNA at any given address (segment), don’t match confirmed maternal and paternal relatives on the same segment, and are confusing imposters.

Are you ready to hit your home run?

What’s Next?

Now that we understand how matching and triangulation works and why, let’s put this to work at the vendors. Join me for my article in a few days, Triangulation in Action at Family Tree DNA, MyHeritage, 23andMe and GedMatch.

We will step through how triangulation works at each vendor. You’ll have matches at each vendor that you don’ t have elsewhere. If you haven’t transferred your DNA file yet, you still have time with the step by step instructions below:

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Disclosure

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Thank you so much.

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Genealogy Services

Genealogy Research

Native American & Minority Ancestors Identified Using DNAPainter Plus Ethnicity Segments

Ethnicity is always a ticklish subject. On one hand we say to be leery of ethnicity estimates, but on the other hand, we all want to know who our ancestors were and where they came from. Many people hope to prove or disprove specific theories or stories about distant ancestors.

Reasons to be cautious about ethnicity estimates include:

  • Within continents, like Europe, it’s very difficult to discern ethnicity at the “country” level because of thousands of years of migration across regions where borders exist today. Ethnicity estimates within Europe can be significantly different than known and proven genealogy.
  • “Countries,” in Europe, political constructs, are the same size as many states in the US – and differentiation between those populations is almost impossible to accurately discern. Think of trying to figure out the difference between the populations of Indiana and Illinois, for example. Yet we want to be able to tell the difference between ancestors that came from France and Germany, for example.

Ethnicity states over Europe

  • All small amounts of ethnicity, even at the continental level, under 2-5%, can be noise and might be incorrect. That’s particularly true of trace amounts, 1% or less. However, that’s not always the case – which is why companies provide those small percentages. When hunting ancestors in the distant past, that small amount of ethnicity may be the only clue we have as to where they reside at detectable levels in our genome.

Noise in this case is defined as:

  • A statistical anomaly
  • A chance combination of your DNA from both parents that matches a reference population
  • Issues with the reference population itself, specifically admixture
  • Perhaps combinations of the above

You can read about the challenges with ethnicity here and here.

On the Other Hand

Having restated the appropriate caveats, on the other hand, we can utilize legitimate segments of our DNA to identify where our ancestors came from – at the continental level.

I’m actually specifically referring to Native American admixture which is the example I’ll be using, but this process applies equally as well to other minority or continental level admixture as well. Minority, in this sense means minority ethnicity to you.

Native American ethnicity shows distinctly differently from African and European. Sometimes some segments of DNA that we inherit from Native American ancestors are reported as Asian, specifically Siberian, Northern or Eastern Asian.

Remember that the Native American people arrived as a small group via Beringia, a now flooded land bridge that once connected Siberia with Alaska.

beringia map

By Erika Tamm et al – Tamm E, Kivisild T, Reidla M, Metspalu M, Smith DG, et al. (2007) Beringian Standstill and Spread of Native American Founders. PLoS ONE 2(9): e829. doi:10.1371/journal.pone.0000829. Also available from PubMed Central., CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=16975303

After that time, the Native American/First Nations peoples were isolated from Asia, for the most part, and entirely from Europe until European exploration resulted in the beginning of sustained European settlement, and admixture beginning in the late 1400s and 1500s in the Americas.

Family Inheritance

Testing multiple family members is extremely useful when working with your own personal minority heritage. This approach assumes that you’d like to identify your matches that share that genetic heritage because they share the same minority DNA that you do. Of course, that means you two share the same ancestor at some time in the past. Their genealogy, or your combined information, may hold the clue to identifying your ancestor.

In my family, my daughter has Native American segments that she inherited from me that I inherited from my mother.

Finding the same segment identified as Native American in several successive generations eliminates the possibility that the chance combination of DNA from your father and mother is “appearing” as Native, when it isn’t.

We can use segment information to our benefit, especially if we don’t know exactly who contributed that DNA – meaning which ancestor.

We need to find a way to utilize those Native or other minority segments genealogically.

23andMe

Today, the only DNA testing vendor that provides consumers with a segment identification of our ethnicity predictions is 23andMe.

If you have tested at 23andMe, sign in and click on Ancestry on the top tab, then select Ancestry Composition.

Minority ethnicity ancestry composition.png

Scroll down until you see your painted chromosomes.

Minority ethnicity chromosome painting.png

By clicking on the region at left that you want to see, the rest of the regions are greyed out and only that region is displayed on your chromosomes, at right.

Minority ethnicity Native.png

According to 23andMe, I have two Native segments, one each on chromosomes 1 and 2. They show these segments on opposite chromosomes, meaning one (the top for example) would be maternal or paternal, and the bottom one would be the opposite. But 23andMe apparently could not tell for sure because neither my mother nor father have tested there. This placement also turned out to be incorrect. The above image was my initial V3 test at 23andMe. My later V4 results were different.

Versions May Differ

Please note that your ethnicity predictions may be different based on which test you took which is dictated by when you took the test. The image above is my V3 test that was in use at 23andMe between 2010 and November 2013, and the image below is my V4 test in use between November 2013 and August 2017.

23andMe apparently does not correct original errors involving what is known as “strand swap” where the maternal and paternal segments are inverted during analysis. My V4 test results are shown below, where the strands are correctly portrayed.

Minority ethnicity Native V4.png

Note that both Native segments are now on the lower chromosome “side” of the pair and the position on the chromosome 1 segment has shifted visually.

Minority ethnicity sides.png

I have not tested at 23andMe on the current V5 GSA chip, in use since August 9, 2017, but perhaps I should. The results might be different yet, with the concept being that each version offers an improvement over earlier versions as science advances.

If your parents have tested, 23andMe makes adjustments to your ethnicity estimates accordingly.

Although my mother can’t test at 23andMe, I happen to already know that these Native segments descend from my mother based on genealogical and genetic analysis, combined. I’m going to walk you through the process.

I can utilize my genealogy to confirm or refute information shown by 23andMe. For example, if one of those segments comes from known ancestors who were living in Germany, it’s clearly not Native, and it’s noise of some type.

We’re going to utilize DNAPainter to determine which ancestors contributed your minority segments, but first you’ll need to download your ethnicity segments from 23andMe.

Downloading Ethnicity Segment Data

Downloading your ethnicity segments is NOT THE SAME as downloading your raw DNA results to transfer to another vendor. Those are two entirely different files and different procedures.

To download the locations of your ethnicity segments at 23andMe, scroll down below your painted ethnicity segments in your Ancestry Composition section to “View Scientific Details.”

MInority ethnicity scientific details.png

Click on View Scientific Details and scroll down to near the bottom and then click on “Download Raw Data.” I leave mine at the 50% confidence level.

Minority ethnicity download raw data.png

Save this spreadsheet to your computer in a known location.

In the spreadsheet, you’ll see columns that provide the name of the segment, the chromosome copy number (1 or 2) and the chromosome number with start and end locations.

Minority ethnicity download.png

You really don’t care about this information directly, but DNAPainter does and you’ll care a lot about what DNAPainter does for you.

DNAPainter

I wrote introductory articles about DNAPainter:

If you’re not familiar with DNAPainter, you might want to read these articles first and then come back to this point in this article.

Go ahead – I’ll wait!

Getting Started

If you don’t have a DNAPainter account, you’ll need to create one for free. Some features, such as having multiple profiles are subscription based, but the functionality you’ll need for one profile is free.

I’ve named this example profile “Ethnicity Demo.” You’ll see your name where mine says “Ethnicity Demo.”

Minority ethnicity DNAPainter.png

Click on “Import 23andme ancestry composition.”

You will copy and paste all the spreadsheet rows in the entire downloaded 23andMe ethnicity spreadsheet into the DNAPainter text box and make your selection, below. The great news is that if you discover that your assumption about copy 1 being maternal or paternal is incorrect, it’s easy to delete the ethnicity segments entirely and simply repaint later. Ditto if 23andMe changes your estimate over time, like they have mine.

Minority ethnicity DNAPainter sides.png

I happen to know that “copy 2” is maternal, so I’ve made that selection.

You can then see your ethnicity chromosome segments painted, and you can expand each one to see the detail. Click on “Save Segments.”

MInority ethnicity DNAPainter Native painting

Click to enlarge

In this example, you can see my Native segments, called by various names at different confidence levels at 23andMe, on chromosome 1.

Depending on the confidence level, these segments are called some mixture of:

  • East Asian & Native American
  • North Asian & Native American
  • Native American
  • Broadly East Asian & Native American

It’s exactly the same segment, so you don’t really care what it’s called. DNAPainter paints all of the different descriptions provided by 23andMe, at all confidence levels as you can see above.

The DNAPainter colors are different from 23andMe colors and are system-selected. You can’t assign the colors for ethnicity segments.

Now, I’m moving to my own profile that I paint with my ancestral segments. To date, I have 78% of my segments painted by identifying cousins with known common ancestors.

On chromosomes 1 and 2, copy 2, which I’ve determined to be my mother’s “side,” these segments track back to specific ancestors.

Minority ethnicity maternal side

Click to enlarge

Chromosome 1 segments, above, track back to the Lore family, descended from Antoine (Anthony) Lore (Lord) who married Rachel Hill. Antoine Lore was Acadian.

Minority ethnicity chromosome 1.png

Clicking on the green segment bar shows me the ancestors I assigned when I painted the match with my Lore family member whose name is blurred, but whose birth surname was Lore.

The Chromosome 2 segment, below, tracks back to the same family through a match to Fred.

Minority ethnicity chromosome 2.png

My common ancestors with Fred are Honore Lore and Marie Lafaille who are the parents of Antoine Lore.

Minority ethnicity common ancestor.png

There are additional matches on both chromosomes who also match on portions of the Native segments.

Now that I have a pointer in the ancestral direction that these Native American segments arrived from, what can traditional genealogy and other DNA information tell me?

Traditional Genealogy Research

The Acadian people were a mixture of English, French and Native American. The Acadians settled on the island of Nova Scotia in 1609 and lived there until being driven out by the English in 1755, roughly 6 or 7 generations later.

Minority ethnicity Acadian map.png

The Acadians intermarried with the Mi’kmaq people.

It had been reported by two very qualified genealogists that Philippe Mius, born in 1660, married two Native American women from the Mi’kmaq tribe given the name Marie.

The French were fond of giving the first name of Marie to Native women when they were baptized in the Catholic faith which was required before the French men were allowed to marry the Native women. There were many Native women named Marie who married European men.

Minority ethnicity Native mitochondrial tree

Click to enlarge

This Mius lineage is ancestral to Antoine Lore (Lord) as shown on my pedigree, above.

Mitochondrial DNA has revealed that descendants from one of Philippe Mius’s wives, Marie, carry haplogroup A2f1a.

However, mitochondrial tests of other descendants of “Marie,” his first wife, carry haplogroup X2a2, also Native American.

Confusion has historically existed over which Marie is the mother of my ancestor, Francoise.

Karen Theroit Reader, another professional genealogist, shows Francoise Mius as the last child born to the first Native wife before her death sometime after 1684 and before about 1687 when Philippe remarried.

However, relative to the source of Native American segments, whether Francoise descends from the first or second wife doesn’t matter in this instance because both are Native and are proven so by their mitochondrial DNA haplogroups.

Additionally, on Antoine’s mother’s side, we find a Doucet male, although there are two genetic male Doucet lines, one of European origin, haplogroup R-L21, and one, surprisingly, of Native origin, haplogroup C-P39. Both are proven by their respective haplogroups but confusion exists genealogically over who descends from which lineage.

On Antoine’s mother’s side, there are several unidentified lineages, any one or multiples of which could also be Native. As you can see, there are large gaps in my tree.

We do know that these Native segments arrived through Antoine Lore and his parents, Honore Lore and Marie LaFaille. We don’t know exactly who upstream contributed these segments – at least not yet. Painting additional matches attributable to specific ancestral couples will eventually narrow the candidates and allow me to walk these segments back in time to their rightful contributor.

Segments, Traditional Research and DNAPainter

These three tools together, when using continent-level segments in combination with painting the DNA segments of known cousins that match specific lineages create a triangulated ethnicity segment.

When that segment just happens to be genealogically important, this combination can point the researchers in the right direction knowing which lines to search for that minority ancestor.

If your cousins who match you on this segment have also tested with 23andMe, they should also be identified as Native on this same segment. This process does not apply to intracontinental segments, meaning within Europe, because the admixture is too great and the ethnicity predictions are much less reliable.

When identifying minority admixture at the continental level, adding Y and mitochondrial DNA testing to the mix in order to positively identify each individual ancestor’s Y and mitochondrial DNA is very important in both eliminating and confirming what autosomal DNA and genealogy records alone can’t do. The base haplogroup as assigned at 23andMe is a good start, but it’s not enough alone. Plus, we only carry one line of mitochondrial DNA and only males carry Y DNA, and only their direct paternal line.

We need Y and mitochondrial DNA matching at FamilyTreeDNA to verify the specific lineage. Additionally, we very well may need the Y and mitochondrial DNA information that we don’t directly carry – but other cousins do. You can read about Y and mitochondrial DNA testing, here.

I wrote about creating a personal DNA pedigree chart including your ancestors’ Y and mitochondrial DNA here. In order to find people descended from a specific ancestor who have DNA tested, I utilize:

  • WikiTree resources and trees
  • Geni trees
  • FamilySearch trees
  • FamilyTreeDNA autosomal matches with trees
  • AncestryDNA autosomal matches and their associated trees
  • Ancestry trees in general, meaning without knowing if they are related to a DNA match
  • MyHeritage autosomal matches and their trees
  • MyHeritage trees in general

At both MyHeritage and Ancestry, you can view the trees of your matches, but you can also search for ancestors in other people’s trees to see who might descend appropriately to provide a Y or mitochondrial DNA sample. You will probably need a subscription to maximize these efforts. My Heritage offers a free trial subscription here.

If you find people appropriately descended through WikiTree, Geni or FamilySearch, you’ll need to discuss DNA testing with them. They may have already tested someplace.

If you find people who have DNA tested through your DNA matches with trees at Ancestry and MyHeritage, you’ll need to offer a Y or mitochondrial DNA test to them if they haven’t already tested at FamilyTreeDNA.

FamilyTreeDNA is the only vendor who provides the Y DNA and mitochondrial DNA tests at the higher resolution level, beyond base haplogroups, required for matching and for a complete haplogroup designation.

If the person has taken the Family Finder autosomal test at FamilyTreeDNA, they may have already tested their Y DNA and mtDNA, or you can offer to upgrade their test.

Projects

Checking projects at FamilyTreeDNA can be particularly useful when trying to discover if anyone from a specific lineage has already tested. There are many, special interest projects such as the Acadian AmerIndian Ancestry project, the American Indian project, haplogroup projects, surname projects and more.

You can view projects alphabetically here or you can click here to scroll down to enter the surname or topic you are seeking.

Minority ethnicity project search.png

If the topic isn’t listed, check the alphabetic index under Geographical Projects.

23andMe Maternal and Paternal Sides

If possible, you’ll want to determine which “side” of your family your minority segments originate come from, unless they come from both. you’ll want to determine whether chromosome side one 1 or 2 is maternal, because the other one will be paternal.

23andMe doesn’t offer tree functionality in the same way as other vendors, so you won’t be able to identify people there descended from your ancestors without contacting each person or doing other sleuthing.

Recently, 23andMe added a link to FamilySearch that creates a list of your ancestors from their mega-shared tree for 7 generations, but there is no tree matching or search functionality. You can read about the FamilySearch connection functionality here.

So, how do you figure out which “side” is which?

Minority ethnicity minority segment.png

The chart above represents the portion of your chromosomes that contains your minority ancestry. Initially, you don’t know if the minority segment is your mother’s pink chromosome or your father’s blue chromosome. You have one chromosome from each parent with the exact same addresses or locations, so it’s impossible to tell which side is which without additional information. Either the pink or the blue segment is minority, but how can you tell?

In my case, the family oral history regarding Native American ancestry was from my father’s line, but the actual Native segments wound up being from my mother, not my father. Had I made an assumption, it would have been incorrect.

Fortunately, in our example, you have both a maternal and paternal aunt who have tested at 23andMe. You match both aunts on that exact same segment location – one from your father’s side, blue, and one from your mother’s side, pink.

You compare your match with your maternal aunt and verify that indeed, you do match her on that segment.

You’ll want to determine if 23andMe has flagged that segment as Native American for your maternal aunt too.

You can view your aunt’s Ancestry Composition by selecting your aunt from the “Your Connections” dropdown list above your own ethnicity chromosome painting.

Minority ethnicity relative connections.png

You can see on your aunt’s chromosomes that indeed, those locations on her chromosomes are Native as well.

Minority ethnicity relative minority segments.png

Now you’ve identified your minority segment as originating on your maternal side.

Minority ethnicity Native side.png

Let’s say you have another match, Match 1, on that same segment. You can easily tell which “side” Match 1 is from. Since you know that you match your maternal aunt on that minority segment, if Match 1 matches both you and your maternal aunt, then you know that’s the side the match is from – AND that person also shares that minority segment.

You can also view that person’s Ancestry Composition as well, but shared matching is more reliable,especially when dealing with small amounts of minority admixture.

Another person, Match 2, matches you on that same segment, but this time, the person matches you and your paternal aunt, so they don’t share your minority segment.

Minority ethnicity match side.png

Even if your paternal aunt had not tested, because Match 2 does not match you AND your maternal aunt, you know Match 2 doesn’t share your minority segment which you can confirm by checking their Ancestry Composition.

Download All of Your Matches

Rather than go through your matches one by one, it’s easiest to download your entire match list so you can see which people match you on those chromosome locations.

Minority ethnicity download aggregate data.png

You can click on “Download Aggregate Data” at 23andMe, at the bottom of your DNA Relatives match list to obtain all of your matches who are sharing with you. 23andMe limits your matches to 2000 or less, the actual number being your highest 2000 matches minus the people who aren’t sharing. I have 1465 matches showing and that number decreases regularly as new testers at 23andMe are focused on health and not genealogy, meaning lower matches get pushed off the list of 2000 match candidates.

You can quickly sort the spreadsheet to see who matches you on specific segments. Then, you can check each match in the system to see if that person matches you and another known relative on the minority segments or you can check their Ancestry Composition, or both.

If they share your minority segment, then you can check their tree link if they have one, included in the download, their Family Search information if included on their account, or reach out to them to see if you might share a known ancestor.

The key to making your ethnicity segment work for you is to identify ancestors and paint known matches.

Paint Those Matches

When searching for matches whose DNA you can attribute to specific ancestors, be sure to check at all 4 places that provide segment information that you can paint:

At GedMatch, you’ll find some people who have tested at the other various vendors, including Ancestry, but unfortunately not everyone uploads. Ancestry doesn’t provide segment information, so you won’t be able to paint those matches directly from Ancestry.

If your Ancestry matches transfer to GedMatch, FamilyTreeDNA or MyHeritage you can view your match and paint your common segments. At GedMatch, Ancestry kit numbers begin with an A. I use my Ancestry kit matches at GedMatch to attempt to figure out who that match is at Ancestry in order to attempt to figure out the common ancestor.

To Paint, You Must Test

Of course, in order to paint your matches that you find in various databases, you need to be in those data bases, meaning you either need to test there or transfer your DNA file.

Transfers

If you’d like to test your DNA at one vendor and download the file to transfer to another vendor, or GedMatch, that’s possible with both FamilyTreeDNA and MyHeritage who both accept uploads.

You can transfer kits from Ancestry and 23andMe to both FamilyTreeDNA and MyHeritage for free, although the chromosome browsers, advanced tools and ethnicity require an unlock fee (or alternatively a subscription at MyHeritage). Still, the free transfer and unlock for $19 at FamilyTreeDNA or $29 at MyHeritage is less than the cost of testing.

Here’s a quick cheat sheet.

DNA vendor transfer cheat sheet 2019

From time to time, as vendor file formats change, the ability to transfer is temporarily interrupted, but it costs nothing to try a transfer to either MyHeritage or FamilyTreeDNA, or better yet, both.

In each of these articles, I wrote about how to download your data from a specific vendor and how to upload from other vendors if they accept uploads.

Summary Steps

In order to use your minority ethnicity segments in your genealogy, you need to:

  1. Test at 23andMe
  2. Identify which parental side your minority ethnicity segments are from, if possible
  3. Download your ethnicity segments
  4. Establish a DNAPainter account
  5. Upload your ethnicity segments to DNAPainter
  6. Paint matches of people with whom you share known common ancestors utilizing segment information from 23andMe, FamilyTreeDNA, MyHeritage and AncestryDNA matches who have uploaded to GedMatch
  7. If you have not tested at either MyHeritage or FamilyTreeDNA, upload your 23andMe file to either vendor for matching, along with GedMatch
  8. Focus on those minority segments to determine which ancestral line they descend through in order to identify the ancestor(s) who provided your minority admixture.

Have fun!

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Disclosure

I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

DNA Purchases and Free Transfers

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Genealogy Research

First Steps When Your DNA Results are Ready – Sticking Your Toe in the Genealogy Water

First steps helix

Recently someone asked me what the first steps would be for a person who wasn’t terribly familiar with genealogy and had just received their DNA test results.

I wrote an article called DNA Results – First Glances at Ethnicity and Matching which was meant to show new folks what the various vendor interfaces look like. I was hoping this might whet their appetites for more, meaning that the tester might, just might, stick their toe into the genealogy waters😊

I’m hoping this article will help them get hooked! Maybe that’s you!

A Guide

This article can be read in one of two ways – as an overview, or, if you click the links, as a pretty thorough lesson. If you’re new, I strongly suggest reading it as an overview first, then a second time as a deeper dive. Use it as a guide to navigate your results as you get your feet wet.

I’ll be hotlinking to various articles I’ve written on lots of topics, so please take a look at details (eventually) by clicking on those links!

This article is meant as a guideline for what to do, and how to get started with your DNA matching results!

If you’re looking for ethnicity information, check out the First Glances article, plus here and here and here.

Concepts – Calculating Ethnicity Percentages provides you with guidelines for how to estimate your own ethnicity percentages based on your known genealogy and Ethnicity Testing – A Conundrum explains how ethnicity testing is done.

OK, let’s get started. Fun awaits!

The Goal

The goal for using DNA matching in genealogy depends on your interests.

  1. To discover cousins and family members that you don’t know. Some people are interested in finding and meeting relatives who might have known their grandparents or great-grandparents in the hope of discovering new family information or photos they didn’t know existed previously. I’ve been gifted with my great-grandparent’s pictures, so this strategy definitely works!
  2. To confirm ancestors. This approach presumes that you’ve done at least a little genealogy, enough to construct at least a rudimentary tree. Ancestors are “confirmed” when you DNA match multiple other people who descend from the same ancestor through multiple children. I wrote an article, Ancestors: What Constitutes Proof?, discussing how much evidence is enough to actually confirm an ancestor. Confirmation is based on a combination of both genealogical records and DNA matching and it varies depending on the circumstances.
  3. Adoptees and people with unknown parents seeking to discover the identities of those people aren’t initially looking at their own family tree – because they don’t have one yet. The genealogy of others can help them figure out the identity of those mystery people. I wrote about that technique in the article, Identifying Unknown Parents and Individuals Using DNA Matching.

DNAAdoption for Everyone

Educational resources for adoptees and non-adoptees alike can be found at www.dnaadoption.org. DNAAdoption is not just for adoptees and provides first rate education for everyone. They also provide trained and mentored search angels for adoptees who understand the search process along with the intricacies of navigating the emotional minefield of adoption and unknown parent searches.

First Look” classes for each vendor are free for everyone at DNAAdoption and are self-paced, downloadable onto your computer as a pdf file. Intro to DNA, Applied Autosomal DNA and Y DNA Basics classes are nominally priced at between $29 and $49 and I strongly recommend these. DNAAdoption is entirely non-profit, so your class fee or contribution supports their work. Additional resources can be found here and their 12 adoptee search steps here.

Ok, now let’s look at your results.

Matches are the Key

Regardless of your goal, your DNA matches are the key to finding answers, whether you want to make contact with close relatives, prove your more distant ancestors or you’re involved in an adoptee or unknown parent search.

Your DNA matches that of other people because each of you inherited a piece of DNA, called a segment, where many locations are identical. The length of that DNA segment is measured in centiMorgans and those locations are called SNPs, or single nucleotide polymorphisms. You can read about the definition of a centimorgan and how they are used in the article Concepts – CentiMorgans, SNPs and Pickin’Crab.

While the scientific details are great, they aren’t important initially. What is important is to understand that the more closely you match someone, the more closely you are related to them. You share more DNA with close relatives than more distant relatives.

For example, I share exactly half of my mother’s DNA, but only about 25% of each of my grandparents’ DNA. As the relationships move further back in time, I share less and less DNA with other people who descend from those same ancestors.

Informational Tools

Every vendor’s match page looks different, as was illustrated in the First Glances article, but regardless, you are looking for four basic pieces of information:

  • Who you match
  • How much DNA you share with your match
  • Who else you and your match share that DNA with, which suggests that you all share a common ancestor
  • Family trees to reveal the common ancestor between people who match each other

Every vendor has different ways of displaying this information, and not all vendors provide everything. For example, 23andMe does not support trees, although they allow you to link to one elsewhere. Ancestry does not provide a tool called a chromosome browser which allows you to see if you and others match on the same segment of DNA. Ancestry only tells you THAT you match, not HOW you match.

Each vendor has their strengths and shortcomings. As genealogists, we simply need to understand how to utilize the information available.

I’ll be using examples from all 4 major vendors:

Your matches are the most important information and everything else is based on those matches.

Family Tree DNA

I have tested many family members from both sides of my family at Family Tree DNA using the Family Finder autosomal test which makes my matches there incredibly useful because I can see which family members, in addition to me, my matches match.

Family Tree DNA assigns matches to maternal and paternal sides in a unique way, even if your parents haven’t tested, so long as some close relatives have tested. Let’s take a look.

First Steps Family Tree DNA matches.png

Sign on to your account and click to see your matches.

At the top of your Family Finder matches page, you’ll see three groups of things, shown below.

First Steps Family Tree DNA bucketing

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A row of tools at the top titled Chromosome Browser, In Common With and Not in Common With.

A second row of tabs that include All, Paternal, Maternal and Both. These are the maternal and paternal tabs I mentioned, meaning that I have a total of 4645 matches, 988 of which are from my paternal side and 847 of which are from my maternal side.

Family Tree DNA assigns people to these “buckets” based on matches with third cousins or closer if you have them attached in your tree. This is why it’s critical to have a tree and test close relatives, especially people from earlier generations like aunts, uncles, great-aunts/uncles and their children if they are no longer living.

If you have one or both parents that can test, that’s a wonderful boon because anyone who matches you and one of your parents is automatically bucketed, or phased (scientific term) to that parent’s side of the tree. However, at Family Tree DNA, it’s not required to have a parent test to have some matches assigned to maternal or paternal sides. You just need to test third cousins or closer and attach them to the proper place in your tree.

How does bucketing work?

Maternal or Paternal “Side” Assignment, aka Bucketing

If I match a maternal first cousin, Cheryl, for example, and we both match John Doe on the same segment, John Doe is automatically assigned to my maternal bucket with a little maternal icon placed beside the match.

First Steps Family Tree DNA match info

Click to enlarge

Every vendor provides an estimated or predicted relationship based on a combination of total centiMorgans and the longest contiguous matching segment. The actual “linked relationship” is calculated based on where this person resides in your tree.

The common surnames at far right are a very nice features, but not every tester provides that information. When the testers do include surnames at Family Tree DNA, common surnames are bolded. Other vendors have similar features.

People with trees are shown near their profile picture with a blue pedigree icon. Clicking on the pedigree icon will show you their ancestors. Your matches estimated relationship to you indicates how far back you should expect to share an ancestor.

For example, first cousins share grandparents. Second cousins share great-grandparents. In general, the further back in time your common ancestor, the less DNA you can be expected to share.

You can view relationship information in chart form in my article here or utilize DNAPainter tools, here, to see the various possibilities for the different match levels.

Clicking on the pedigree chart of your match will show you their tree. In my tree, I’ve connected my parents in their proper places, along with Cheryl and Don, mother’s first cousins. (Yes, they’ve given permission for me to utilize their results, so they aren’t always blurred in images.)

Cheryl and Don are my first cousins once removed, meaning my mother is their first cousin and I’m one generation further down the tree. I’m showing the amount of DNA that I share with each of them in red in the format of total DNA shared and longest unbroken segment, taken from the match list. So 382-53 means I share a total of 382 cM and 53 cM is the longest matching block.

First Steps Family Tree DNA tree.png

The Chromosome Browser

Utilizing the chromosome browser, I can see exactly where I match both Don and Cheryl. It’s obvious that I match them on at least some different pieces of my DNA, because the total and longest segment amounts are different.

The reason it’s important to test lots of close relatives is because even siblings inherit different pieces of DNA from their parents, and they don’t pass the same DNA to their offspring either – so in each generation the amount of shared DNA is probably reduced. I say probably because sometimes segments are passed entirely and sometimes not at all, which is how we “lose” our ancestors’ DNA over the generations.

Here’s a matching example utilizing a chromosome browser.

First Steps Family Tree DNA chromosome browser.png

I clicked the checkboxes to the left of both Cheryl and Don on the match page, then the Chromosome Browser button, and now you can see, above, on chromosomes 1-16 where I match Cheryl (blue) and Don (red.)

In this view, both Don and Cheryl are being compared to me, since I’m the one signed in to my account and viewing my DNA matches. Therefore, one of the bars at each chromosome represents Don’s DNA match to me and one represents Cheryl’s. Cheryl is the first person and Don is the second. Person match colors (red and blue) are assigned arbitrarily by the system.

My grandfather and Cheryl/Don’s father, Roscoe, were siblings.

You can see that on some segments, my grandfather and Roscoe inherited the same segment of DNA from their parents, because today, my mother gave me that exact same segment that I share with both Don and Cheryl. Those segments are exactly identical and shown in the black boxes.

The only way for us to share this DNA today is for us to have shared a common ancestor who gave it to two of their children who passed it on to their descendants who DNA tested today.

On other segments, in red boxes, I share part of the same segments of DNA with Cheryl and Don, but someone along the line didn’t inherit all of that segment. For example on chromosome 3, in the red box, you can see that I share more with Cheryl (blue) than Don (red.)

In other cases, I share with either Don or Cheryl, but Don and Cheryl didn’t inherit that same segment of DNA from their father, so I don’t share with both of them. Those are the areas where you see only blue or only red.

On chromosome 12, you can see where it looks like Don’s and Cheryl’s segments butt up against each other. The DNA was clearly divided there. Don received one piece and Cheryl got the other. That’s known as a crossover and you can read about crossovers here, if you’d like.

It’s important to be able to view segment information to be able to see how others match in order to identify which common ancestor that DNA came from.

In Common With

You can use the “In Common With” tool to see who you match in common with any match. My first 6 matches in common with Cheryl are shown below. Note that they are already all bucketed to my maternal side.

First Steps Family Tree DNA in common with

click to enlarge

You can click on up to 7 individuals in the check box at left to show them on the chromosome browser at once to see if they match you on common segments.

Each matching segment has its own history and may descend from a different ancestor in your common tree.

First Steps 7 match chromosome browser

click to enlarge

If combinations of people do match me on a common segment, because these matches are all on my maternal side, they are triangulated and we know they have to descend from a common ancestor, assuming the segment is large enough. You can read about the concept of triangulation here. Triangulation occurs when 3 or more people (who aren’t extremely closely related like parents or siblings) all match each other on the same reasonably sized segment of DNA.

If you want to download your matches and work through this process in a spreadsheet, that’s an option too.

Size Matters

Small segments can be identical by chance instead of identical by descent.

  • “Identical by chance” means that you accidentally match someone because your DNA on that segment has been combined from both parents and causes it to match another person, making the segment “looks like” it comes from a common ancestor, when it really doesn’t. When DNA is sequenced, both your mother and father’s strands are sequenced, meaning that there’s no way to determine which came from whom. Think of a street with Mom’s side and Dad’s side with identical addresses on the houses on both sides. I wrote about that here.
  • “Identical by descent” means that the DNA is identical because it actually descends from a common ancestor. I discussed that concept in the article, We Match, But Are We Related.

Generally, we only utilize 7cM (centiMorgan) segments and above because at that level, about half of the segments are identical by descent and about half are identical by chance, known as false positives. By the time we move above 15 cM, most, but not all, matches are legitimate. You can read about segment size and accuracy here.

Using “In Common With” and the Matrix

“In Common With” is about who shares DNA. You can select someone you match to see who else you BOTH match. Just because you match two other people doesn’t necessarily mean that it’s on the same segment of DNA. In fact, you could match one person from your mother’s side and the other person from your father’s side.

First Steps match matrix.png

In this example, you match Person B due to ancestor John Doe and Person C due to ancestor Susie Smith. However, Person B also matches person C, but due to ancestor William West that they share and you don’t.

This example shows you THAT they match, but not HOW they match.

The only way to assure that the matches between the three people above are due to the same ancestor is to look at the segments with a chromosome browser and compare all 3 people to each other. Finding 3 people who match on the same segment, from the same side of your tree means that (assuming a reasonably large segment) you share a common ancestor.

Family Tree DNA has a nice matrix function that allows you to see which of your matches also match each other.

First steps matrix link

click to enlarge

The important distinction between the matrix and the chromosome browser is that the chromosome browser shows you where your matches match you, but those matches could be from both sides of your tree, unless they are bucketed. The matrix shows you if your matches also match each other, which is a huge clue that they are probably from the same side of your tree.

First Steps Family Tree DNA matrix.png

A matrix match is a significant clue in terms of who descends from which ancestors. For example, I know, based on who Amy matches, and who she doesn’t match, that she descends from the Ferverda side and that Charles, Rex and Maxine descend from ancestors on the Miller side.

Looking in the chromosome browser, I can tell that Cheryl, Don, Amy and I match on some common segments.

Matching multiple people on the same segment that descends from a common ancestor is called triangulation.

Let’s take a look at the MyHeritage triangulation tool.

MyHeritage

Moving now to MyHeritage who provides us with an easy to use triangulation tool, we see the following when clicking on DNA matches on the DNA tab on the toolbar.

First Steps MyHeritage matches

click to enlarge

Cousin Cheryl is at MyHeritage too. By clicking on Review DNA Match, the purple button on the right, I can see who else I match in common with Cheryl, plus triangulation.

The list of people Cheryl and I both match is shown below, along with our relationships to each person.

First Steps MyHeritage triangulation

click to enlarge

I’ve selected 2 matches to illustrate.

The first match has a little purple icon to the right which means that Amy triangulates with me and Cheryl.

The second match, Rex, means that while we both match Rex, it’s not on the same segment. I know that without looking further because there is no triangulation button. We both match Rex, but Cheryl matches Rex on a different segment than I do.

Without additional genealogy work, using DNA alone, I can’t say whether or not Cheryl, Rex and I all share a common ancestor. As it turns out, we do. Rex is a known cousin who I tested. However, in an unknown situation, I would have to view the trees of those matches to make that determination.

Triangulation

Clicking on the purple triangulation icon for Amy shows me the segments that all 3 of us, me, Amy and Cheryl share in common as compared to me.

First Steps MyHeritage triangulation chromosome browser.png

Cheryl is red and Amy is yellow. The one segment bracketed with the rounded rectangle is the segment shared by all 3 of us.

Do we have a common ancestor? I know Cheryl and I do, but maybe I don’t know who Amy is. Let’s look at Amy’s tree which is also shown if I scroll down.

First Steps MyHeritage common ancestor.png

Amy didn’t have her tree built out far enough to show our common ancestor, but I immediately recognized the surname Ferveda found in her tree a couple of generations back. Darlene was the daughter of Donald Ferverda who was the son of Hiram Ferverda, my great-grandfather.

Hiram was the father of Cheryl’s father, Roscoe and my grandfather, John Ferverda.

First Steps Hiram Ferverda pedigree.png

Amy is my first cousin twice removed and that segment of DNA that I share with her is from either Hiram Ferverda or his wife Eva Miller.

Now, based on who else Amy matches, I can probably tell whether that segment descends from Hiram or Eva.

Viva triangulation!

Theory of Family Relativity

MyHeritage’s Theory of Family Relativity provides theories to people whose DNA matches regarding their common ancestor if MyHeritage can calculate how the 2 people are potentially related.

MyHeritage uses a combination of tools to make that connection, including:

  • DNA matches
  • Your tree
  • Your match’s tree
  • Other people’s trees at MyHeritage, FamilySearch and Geni if the common ancestor cannot be found in your tree compared against your DNA match’s MyHeritage
  • Documents in the MyHeritage data collection, such as census records, for example.

MyHeritage theory update

To view the Theories, click on the purple “View Theories” banner or “View theory” under the DNA match.

First Steps MyHeritage theory of relativity

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The theory is displayed in summary format first.

MyHeritage view full theory

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You can click on the “View Full Theory” to see the detail and sources about how MyHeritage calculated various paths. I have up to 5 different theories that utilize separate resources.

MyHeritage review match

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A wonderful aspect of this feature is that MyHeritage shows you exactly the information they utilized and calculates a confidence factor as well.

All theories should be viewed as exactly that and should be evaluated critically for accuracy, taking into consideration sources and documentation.

I wrote about using Theories of Relativity, with instructions, here and here.

I love this tool and find the Theories mostly accurate.

AncestryDNA

Ancestry doesn’t offer a chromosome browser or triangulation but does offer a tree view for people that you match, so long as you have a subscription. In the past, a special “Light” subscription for DNA only was available for approximately $49 per year that provided access to the trees of your DNA matches and other DNA-related features. You could not order online and had to call support, sometimes asking for a supervisor in order to purchase that reduced-cost subscription. The “Light” subscription did not provide access to anything outside of DNA results, meaning documents, etc. I don’t know if this is still available.

After signing on, click on DNA matches on the DNA tab on the toolbar.

You’ll see the following match list.

First Steps Ancestry matches

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I’ve tested twice at Ancestry, the second time when they moved to their new chip, so I’m my own highest match. Click on any match name to view more.

First Steps Ancestry shared matches

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You’ll see information about common ancestors if you have some in your trees, plus the amount of shared DNA along with a link to Shared Matches.

I found one of the same cousins at Ancestry whose match we were viewing at MyHeritage, so let’s see what her match to me at Ancestry looks like.

Below are my shared matches with that cousin. The notes to the right are mine, not provided by Ancestry. I make extensive use of the notes fields provided by the vendors.

First Steps Ancestry shared matches with cousin

click to enlarge

On your match list, you can click on any match, then on Shared Matches to see who you both match in common. While Ancestry provides no chromosome browser, you can see the amount of DNA that you share and trees, if any exist.

Let’s look at a tree comparison when a common ancestor can be detected in a tree within the past 7 generations.

First Steps Ancestry view ThruLines.png

What’s missing of course is that I can’t see how we match because there’s no chromosome browser, nor can I see if my matches match each other.

Stitched Trees

What I can see, if I click on “View ThruLines” above or ThruLines on the DNA Summary page on the main DNA tab is all of the people I match who Ancestry THINKS we descend from a common ancestor. This ancestor information isn’t always taken from either person’s tree.

For example, if my match hadn’t included Hiram Ferverda in her tree, Ancestry would use other people’s trees to “stitch them together” such that the tester is shown to be descended from a common ancestor with me. Sometimes these stitched trees are accurate and sometimes they are not, although they have improved since they were first released. I wrote about ThruLines here.

First Steps Ancestry ThruLines tree

click to enlarge

In closer generations, especially if you are looking to connect with cousins, tree matching is a very valuable tool. In the graphic above, you can see all of the cousins who descend from Hiram Ferverda who have tested and DNA match to me. These DNA matches to me either descend from Hiram according to their trees, or Ancestry believes they descend from Hiram based on other people’s trees.

With more distant ancestors, other people’s trees are increasingly likely to be copied with no sources, so take them with a very large grain of salt (perchance the entire salt lick.) I use ThruLines as hints, not gospel, especially the further back in time the common ancestor. I wish they reached back another couple of generations. They are great hints and they end with the 7th generation where my brick walls tend to begin!

23andMe

I haven’t mentioned 23andMe yet in this article. Genealogists do test there, especially adoptees who need to fish in every pond.

23andMe is often the 4th choice of the major 4 vendors for genealogy due to the following challenges:

  • No tree support, other than allowing you to link to a tree at FamilySearch or elsewhere. This means no tree matching.
  • Less than 2000 matches, meaning that every person is limited to a maximum of 2000 matches, minus however many of those 2000 don’t opt-in for genealogical matching. Given that 23andMe’s focus is increasingly health, my number of matches continues to decrease and is currently just over 1500. The good news is that those 1500 are my highest, meaning closest matches. The bad news is the genealogy is not 23andMe’s focus.

If you are an adoptee, a die-hard genealogist or specifically interested in ethnicity, then test at 23andMe. Otherwise all three of the other vendors would be better choices.

However, like the other vendors, 23andMe does have some features that are unique.

Their ethnicity predictions are acknowledged to be excellent. Ethnicity at 23andMe is called Ancestry Composition, and you’ll see that immediately when you sign in to your account.

First Steps 23andMe DNA Relatives.png

Your matches at 23andMe are found under DNA Relatives.

First Steps 23andMe tools

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At left, you’ll find filters and the search box.

Mom’s and Dad’s side filter matches if you’ve tested your parents, but it’s not like the Family Tree DNA bucketing that provides maternal and paternal side bucketing by utilizing through third cousins if your parents aren’t available for testing.

Family names aren’t your family names, but the top family names that match to you. Guess what my highest name is? Smith.

However, Ancestor Birthplaces are quite useful because you can sort by country. For example, my mother’s grandfather Ferverda was born in the Netherlands.

First Steps 23andMe country.png

If I click on Netherlands, I can see my 5 matches with ancestors born in the Netherlands. Of course, this doesn’t mean that I match because of my match’s Dutch ancestors, but it does provide me with a place to look for a common ancestor and I can proceed by seeing who I match in common with those matches. Unfortunately, without trees we’re left to rely on ancestor birthplaces and family surnames, if my matches have entered that information.

One of my Dutch matches also matches my Ferverda cousin. Given that connection, and that the Ferverda family immigrated from Holland in 1868, that’s a starting point.

MyHeritage has a similar features and they are much more prevalent in Europe.

By clicking on my Ferverda cousin, I can view the DNA we share, who we match in common, our common ethnicity and more. I have the option of comparing multiple people in the chromosome browser by clicking on “View DNA Comparison” and then selecting who I wish to compare.

First Steps 23andMe view DNA Comparison.png

By scrolling down instead of clicking on View DNA Comparison, I can view where my Ferverda cousin matches me on my chromosomes, shown below.

First STeps 23andMe chromosome browser.png

23andMe identifies completely identical segments which would be painted in dark purple, the legend at bottom left.

Adoptees love this feature because it would immediately differentiate between half and full siblings. Full siblings share approximately 25% of the exact DNA on both their maternal and paternal strands of DNA, while half siblings only share the DNA from one parent – assuming their parents aren’t closely related. I share no completely identical DNA with my Ferverda cousin, so no segments are painted dark purple.

23andMe and Ancestry Maps Show Where Your Matches Live

Another reason that adoptees and people searching for birth parents or unknown relatives like 23andMe is because of the map function.

After clicking on DNA Relatives, click on the Map function at the top of the page which displays the following map.

First Steps 23andMe map

click to enlarge

This isn’t a map of where your matches ancestors lived, but is where your matches THEMSELVES live. Furthermore, you can zoom in, click on the button and it displays the name of the individual and the city where they live or whatever they entered in the location field.

First Steps 23andMe your location on map.png

I entered a location in my profile and confirmed that the location indeed displays on my match’s maps by signing on to another family member’s account. What I saw is the display above. I’d wager that most testers don’t realize that their home location and photo, if entered, is being displayed to their matches.

I think sharing my ancestors’ locations is a wonderful, helpful, idea, but there is absolutely no reason whatsoever for anyone to know where I live and I feel it’s stalker-creepy and a safety risk.

First Steps 23andMe questions.png

If you enter a location in this field in your profile, it displays on the map.

If you test with 23andMe and you don’t want your location to display on this map to your matches, don’t answer any question that asks you where you call home or anything similar. I never answer any questions at 23andMe. They are known for asking you the same question repeatedly, in multiple locations and ways, until you relent and answer.

Ancestry has a similar map feature and they’ve also begun to ask you questions that are unrelated to genealogy.

Ancestry Map Shows Where Your Matches Live

At Ancestry, when you click to see your DNA matches, look to the right at the map link.

First Steps Ancestry map link.png

By clicking on this link, you can see the locations that people have entered into their profile.

First Steps Ancestry match map.png

As you can see, above, I don’t have a location entered and I am prompted for one. Note that Ancestry does specifically say that this location will be shown to your matches.

You can click on the Ancestry Profile link here, or go to your Personal Profile by click the dropdown under your user name in the upper right hand corner of any page.

This is important because if you DON’T want your location to show, you need to be sure there is nothing entered in the location field.

First Steps Ancestry profile.png

Under your profile, click “Edit.”

First Steps Ancestry edit profile.png

After clicking edit, complete the information you wish to have public or remove the information you do not.

First Steps Ancestry location in profile.png

Sometimes Your Answer is a Little More Complicated

This is a First Steps article. Sometimes the answer you seek might be a little more complicated. That’s why there are specialists who deal with this all day, everyday.

What issues might be more complex?

If you’re just starting out, don’t worry about these things for now. Just know when you run into something more complex or that doesn’t make sense, I’m here and so are others. Here’s a link to my Help page.

Getting Started

What do you need to get started?

  • You need to take a DNA test, or more specifically, multiple DNA tests. You can test at Ancestry or 23andMe and transfer your results to both Family Tree DNA and MyHeritage, or you can test directly at all vendors.

Neither Ancestry nor 23andMe accept uploads, meaning other vendors tests, but both MyHeritage and Family Tree DNA accept most file versions. Instructions for how to download and upload your DNA results are found below, by vendor:

Both MyHeritage and Family Tree DNA charge a minimal fee to unlock their advanced features such as chromosome browsers and ethnicity if you upload transfer files, but it’s less costly in both cases than testing directly. However, if you want the MyHeritage DNA plus Health or the Family Tree DNA Y DNA or Mitochondrial DNA tests, you must test directly at those companies for those tests.

  • It’s not required, but it would be in your best interest to build as much of a tree at all three vendors as you can. Every little bit helps.

Your first tree-building step should be to record what your family knows about your grandparents and great-grandparents, aunts and uncles. Here’s what my first step attempt looked like. It’s cringe-worthy now, but everyone has to start someplace. Just do it!

You can build a tree at either Ancestry or MyHeritage and download your tree for uploading at the other vendors. Or, you can build the tree using genealogy software on your computer and upload to all 3 places. I maintain my primary tree on my computer using RootsMagic. There are many options. MyHeritage even provides free tree builder software.

Both Ancestry and MyHeritage offer research/data subscriptions that provide you with hints to historical documents that increase what you know about your ancestors. The MyHeritage subscription can be tried for free. I have full subscriptions to both Ancestry and MyHeritage because they both include documents in their collections that the other does not.

Please be aware that document suggestions are hints and each one needs to be evaluated in the context of what you know and what’s reasonable. For example, if your ancestor was born in 1750, they are not included in the 1900 census, nor do women have children at age 70. People do have exactly the same names. FindAGrave information is entered by humans and is not always accurate. Just sayin’…

Evaluate critically and skeptically.

Ok, Let’s Go!

When your DNA results are ready, sign on to each vendor, look at your matches and use this article to begin to feel your way around. It’s exciting and the promise is immense. Feel free to share the link to this article on social media or with anyone else who might need help.

You are the cumulative product of your ancestors. What better way to get to know them than through their DNA that’s shared between you and your cousins!

What can you discover today?

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Disclosure

I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

DNA Purchases and Free Transfers

Genealogy Services

Genealogy Research

When DNA Leads You Astray

I’m currently going through what I refer to as “the great purge.”

This occurs when you can’t stand the accumulated piles and boxes of “stuff” and the file drawers are full, so you set about throwing away and giving away. (Yes, I know you just cringed. Me too.)

The great news is that I’ve run across so much old (as in decades old) genealogy from when I first began this journey. I used to make lists of questions and a research “to do” list. I was much more organized then, but there were also fewer “squirrel moments” available online to distract me with “look here, no, over here, no, wait….”

Most of those questions on my old genealogy research lists have (thankfully) since been answered, slowly, one tiny piece of evidence at a time. Believe me, that feeling is very rewarding and while on a daily basis we may not think we’re making much progress; in the big picture – we’re slaying that dragon!

However, genealogy is also fraught with landmines. If I had NOT found the documentation before the days of DNA testing, I could easily have been led astray.

“What?”, you ask, but “DNA doesn’t lie.” No, it doesn’t, but it will sure let you kid yourself about some things.

DNA is a joker and has no problem allowing you to fool yourself and by virtue of that, others as well.

Joke’s On Me

Decades ago, Aunt Margaret told me that her grandmother’s mother was “a Rosenbalm from up on the Lee County (VA) border.”

Now, at that time, I had absolutely NO reason to doubt what she said. After all, it’s her grandmother, Margaret Claxton/Clarkson who she knew personally, who didn’t pass away until my aunt was in her teens. Plenty close enough to know who Margaret Claxton’s mother was. Right?

DNA Astray Rosenbalm

Erroneous pedigree chart. Rebecca Rosenbalm is NOT the mother of Elizabeth Claxton/Clarkson.

I filled Rebecca Rosenbalm’s name into the appropriate space on my pedigree chart, was happy and smugly smiling like a Cheshire cat, right up until I accidentally discovered that the information was just plain wrong.

Uh oh….

Time Rolls On

As records became increasingly available, both in transcribed fashion and online, Hancock County, TN death certificates eventually could be obtained, one way or another. Being a dutiful genealogist, I collected all relevant documents for my ancestors, contentedly filing them in the “well that’s done” category – that is right up until Margaret Clarkson Bolton’s death certificate stopped me dead in my tracks.

margaret clarkson bolton death

Oops

Margaret’s mother wasn’t listed as Rebecca Rosenbalm, nor Rebecca anyone. She was listed as Betsy Speaks. Or was it Spears? In our family, Betsy is short for Elizabeth.

Who the heck was Elizabeth Speaks, or Spears. This was one fine monkey wrench!

A trip to Hancock County, Tennessee was in order.

I dug through dusty deed and court records, sifted through the archives in basements and the old jail building where I just KNEW my ancestors had inhabited cells at one time or another.

Yes, my ancestor’s records really were in jail!

Records revealed that the woman in question was Elizabeth Speaks, not Spears, although the Spears family did live in the area and had “married in” to many local families. Nothing is ever simple and our ancestors do have a perverse sense of humor.

Elizabeth Speak(s) was the daughter of Charles Speak, and the Speak family lived a few miles across the border into Lee County, Virginia. This high mountain land borders two states and three counties, so records are scattered among them – not to mention two fires in the Hancock County courthouse make research challenging.

Why?

I asked my Aunt Margaret who was still living at the time about this apparent discrepancy and she told me that the Rosenbalms “up in Rose Hill, Virginia” told her that her grandmother, Margaret Claxton/Clarkson was kin to them, so Margaret had assumed (there’s that word again) that Margaret Claxton’s mother was their Rebecca Rosenbalm.

Wrong!

The Kernel of Truth

Like so many family stories, there is a kernel of truth, surrounded by a multitude errors. Distilling the grain of truth is the challenge of course.

Margaret Claxton’s mother was Elizabeth (Betsy) Speak and her father was Charles Speak. Charles Speak’s sister, Rebecca married William Henderson Rosenbalm in 1854, had 4 children and died in February 1859. So there indeed was a woman named Rebecca (Speaks) Rosenbalm who had died young and wasn’t well known.

Rebecca’s sister Frances “Fanny” Speak also married that same William Henderson Rosenbalm in November 1859, a few months after Rebecca had died. Fannie also had 4 children, one of which was also named Rebecca Rosenbalm. Do you see a trend here?

So, indeed there were 7 living Rosenbalm children who were first cousins to Elizabeth Speak who married Samuel Claxton and lived a dozen miles away, over the mountains and across the Powell River. Now a dozen miles might not sound like much today, but in the mountains during horse and wagon days – 10 miles wasn’t trivial and required a multi-day commitment for a visit. In other words, the next generation of the family knew of their cousins but didn’t know them well.

The following generation included my Aunt Margaret who was told by those cousins that she was related to them through the Rosenbalm family. While, that was true for the Rosenbalm cousins, it was not true for Aunt Margaret who was related to the Rosenbalms through their common Speak ancestor.

Here’s what the family tree really looks like, only showing the lines under discussion.

DNA astray correct pedigree

You can see why Aunt Margaret might not know specifics. She was actually several generations removed from the common ancestor. She knew THAT they were related, but not HOW they were related and there were several Rebecca’s in several branches of the family.

Why Does This Matter?

You’ve probably guessed by now that someplace in here, there’s a moral to this story, so here it is!

You may have already surmised that I have autosomal DNA matches to cousins through the Rosenbalm/Speaks line.

DNA astray pedigree match

This is one example, but there are more, some being double cousins meaning two of Nicholas Speak’s 11 children’s descendants have intermarried. Life is a lot more complex in those hills and hollers than people think – and unraveling the relationships, both paper and genetic (which are sometimes two different things) is challenging.

DNA astray chromosome 10.png

I match this fourth cousin once removed (4C1R) on a healthy 18 cM segment on chromosome 10.

Wrong Conclusions

Now, think back to where I was originally in my research. I knew that Margaret Claxton/Clarkson was my aunt’s grandmother. I knew nothing at all about the Speak family and had never heard that surname.

Had I ONLY been looking to confirm the Rosenbalm connection, I certainly would have confirmed that I’m related to the Rosenbalm family descendants with this match. Except the conclusion that I descend from a Rosenbalm ancestor would have been WRONG. What we share are the Speak ancestors.

So really, the DNA didn’t lie, but unless I dissected what the DNA match was really telling me carefully and methodically with NO PRECONCEIVED NOTIONS, I would have “confirmed” erroneous information. Or, at least I would have thought that I confirmed it.

I would actually have been doing something worse meaning convincing myself of “facts” that weren’t accurate, which means I would have then been spreading around those cancerous bad trees. Guaranteed, I do NOT want to be that person.

Foolers

I can tell you here and now that I have found several matches that were foolers because I share multiple ancestors with a person that I match, even if those multiple ancestors aren’t known to either or both of us. Every single DNA segment has its own unique history. I match one individual on two segments, one segment through my mom and one segment through my dad. Fortunately, we’ve identified both ancestors now, but imaging my initial surprise and confusion, especially given that my parents don’t share any common ancestors, communities or locations.

We have to evaluate all of the evidence to confirm that the conclusion being drawn in accurate.

DNA astray painting

One of the sanity checks I use, in addition to triangulation, is to paint my matches with known ancestors on my chromosomes using DNAPainter. Here’s the match to my cousin, and it overlaps with other people who share the same ancestor couple. Several matches are obscured behind the black box. If I discover someone that I supposedly match from a different ancestor couple sharing this segment of my father’s DNA, that’s a red neon flashing sign that something is wrong and I need to figure out what and why.

Ignoring this problem and hoping it will go away doesn’t work. I’ve tried😊

Three possible things can be wrong:

  1. The segment is identical by chance, not by descent. With a segment of 18 cM, that’s extremely unlikely. Triangulation with other people on this same segment on the same parent’s side should eliminate most false matches over 7cM. The larger the match, the more likely it is NOT identical by chance, meaning that it IS identical by descent or genealogically relevant.
  2. The segment is accurately matched but the genealogy is confused – such as my Rosenbalm example. This can happen with multiple ancestors, or descent from the same family but through an unknown connection. Looking for other connections to this family and sorting through matches’ trees often provides hints that resolve this situation. In my case, I might have noticed that I matched other people who descended from Nicholas Speak, which would not have been the case had I descended through the Rosenbalm family.
  3. The third scenarios is that the genealogy is plain flat out wrong. Yea, I know this one hurts. Get the saw ready.

The Devil in the Details

Always evaluate your matches in light of what you don’t know, not in order to confirm what you think you know. Play the devil’s advocate – all the time. After all, the devil really is in the details.

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Disclosure

I receive a small contribution when you click on some (but not all) of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

DNA Purchases and Free Transfers

Genealogy Services

Genealogy Research

MyHeritage LIVE Conference Day 2 – The Science Behind DNA Matching    

The MyHeritage LIVE Oslo conference is but a fond memory now, and I would count it as a resounding success.

Perhaps one of the reasons I enjoyed it so much is the scientific aspect and because the content is very focused on a topic I enjoy without being the size and complexity of Rootstech. The smaller, more intimate venue also provides access to the “right” people as well as the ability to meet other attendees and not be overwhelmed by the sheer size.

Here are some stats:

  • 401 registered guests
  • 28 countries represented including distant places like Australia and South America
  • More than 20 speakers plus the hands-on workshops where specialist teams worked with students
  • 38 sessions and workshops, plus the party
  • 60,000 livestream participants, in spite of the time differences around the world

I was blown away by the number of livestream attendees.

I don’t know what criteria Gilad Japhet will be using to determine “success” but I can’t imagine this conference being judged as anything but.

Let’s take a look at the second day. I spent part of the time talking to people and drifting in and out of the rear of several sessions for a few minutes. I meant to visit some of the workshops, but there was just too much good, distracting content elsewhere.

I began Sunday in Mike Mansfield’s presentation about SuperSearch. Yes, I really did attend a few sessions not about DNA, but my favorite was the session on Improved DNA Matching.

Improved DNA Matching

I’m sure it won’t surprise any of my readers that my favorite presentations were about the actual science of genetic genealogy.

Consumers don’t really need to understand the science behind autosomal results to reap the benefits, but the underlying science is part of what I love – and it’s important for me to understand the underpinnings to be able to unravel the fine points of what the resulting matches are and are not revealing. Misinterpretation of DNA results leading to faulty conclusions is a real issue in genetic genealogy today. Consequently, I feel that anyone working with other people’s results and providing advice really needs to understand how the science and technology together works.

Dr. Daphna Weissglas-Volkov, a population geneticist by training, although she clearly functions far beyond that scope today, gave a very interesting presentation about how MyHeritage handles (their greatly improved) DNA Matching. I’m hitting the high points here, but I would strongly encourage you to watch the video of this session when they are made available online.

In addition to Dr. Weissglas-Volkov’s slides, I’ve added some additional explanations and examples in various places. You can easily tell that the slides are hers and the graphics that aren’t MyHeritage slides are mine.

Dr. Weissglas-Volkov began the session by introducing the MyHeritage science team and then explaining terminology to set the stage.

A match is when two people match each other on a fairly long piece of DNA. Of course, “fairly long” is defined differently by each vendor.

Your genetic map (of your chromosomes) is comprised of the DNA you inherit from different ancestors by the process of recombination when DNA is transferred from the parents to the child. A centiMorgan is the relatively likelihood that a recombination will occur in a single generation. On average, 36 recombinations occur in each generation, meaning that the DNA is divided on any chromosome. However, women, for reasons unknown have about 1.5 times as many recombinations as men.

You can’t see that when looking at an example of a person compared to their parents, of course, because each individual is a full match to each parent, but you can see this visually when comparing a grandchild to their maternal grandmother and their paternal grandmother on a chromosome browser.

The above illustration is the same female grandchild compared to her maternal grandmother, at left, and her paternal grandmother at right. Therefore the number of crossovers at left is through a female child (her mother), and the number at right is through a male child (her father.)

# of Crossovers
Through female child – left 57
Through male child – right 22

There are more segments at left, through the mother, and the segments are generally shorter, because they have been divided into more pieces.

At right, fewer and larger segments through the father.

Keep in mind that because you have a strand of DNA from each parent, with exactly the same “street addresses,” that what is produced by DNA sequencing are two columns of data – but your Mom’s and Dad’s DNA is intermixed.

The information in the two columns can’t be identified as Mom’s or Dad’s DNA or strand at this point.

That interspersed raw data is called a genotype. A haplotype is when Mom’s and Dad’s DNA can be reassembled into “sides” so you can attribute the two letters at each address to either Mom or Dad.

Here’s a quick example.

The goal, of course, is to figure out how to reassemble your DNA into Mom’s side and Dad’s side so that we know that someone matching you is actually matching on all As (Mom) or all Gs (Dad,) in this example, and not a false match that zigzags back and forth between Mom and Dad.

The best way to accomplish that goal of course is trio phasing, when the child and both parents are available, so by comparing the child’s DNA with the parents you can assign the two strands of the child’s DNA.

Unfortunately, few people have both or even one parent available in order to actual divide their DNA into “sides,” so the next best avenue is statistical phasing. I’ve called this academic phasing in the past, as compared to parental phasing which MyHeritage refers to as trio phasing.

There’s a huge amount of confusion about phasing, with few people understanding there are two distinct types.

Statistical phasing is a type of machine learning where a large number of reference populations are studied. Since we know that DNA travels together in blocks when inherited, statistical phasing learns which DNA travels with which buddy DNA – and creates probabilities. Your DNA is then compared to these models and your DNA is reshuffled in order to assemble your DNA into two groups – one representing your Mom’s DNA and one representing your Dad’s DNA, according to statistical probability.

Looking at your genotype, if we know that As group together at those 6 addresses in my example 95% of the time, then we know that the most likely scenario to create a haplotype is that all of the As came from one parent and all of the Gs from the other parent – although without additional information, there is no way to yet assign the maternal and paternal identifier. At this point, we only know parent 1 and parent 2.

In order to train the computers (machine learning) to properly statistically phase testers’ results, MyHeritage uses known relationships of people to teach the machines. In other words, their reference panels of proven haplotypes grows all of the time as parent/child trios test.

Dr. Weissglas-Volkev then moved on to imputation.

When sequencing DNA, not every location reads accurately, so the missing values can be imputed, or “put back” using imputation.

Initially imputation was a hot mess. Not just for MyHeritage, but for all vendors, imputation having been forced upon them (and therefore us) by Illumina’s change to the GSA chip.

However, machine learning means that imputation models improve constantly, and matching using imputation is greatly improved at MyHeritage today.

Imputation can do more than just fill in blanks left by sequencing read errors.

The benefit of imputation to the genetic genealogy community is that vendors using disparate chips has forced vendors that want to allow uploads to utilize imputation to create a global template that incorporates all of the locations from each vendor, then impute the values they don’t actually test for themselves to complete the full template for each person.

In the example below, you can see that no vendor tests all available locations, but when imputation extends the sequences of all testers to the full 1-500 locations, the results can easily be compared to every other tester because every tester now has values in locations 1-500, regardless of which vendor/chip was utilized in their actual testing.

Therefore, using imputation, MyHeritage is able to match between quite disparate chips, such as the traditional Illumina chips (OmniExpress), the custom Ancestry chip and the new GSA chip utilized by 23andMe and LivingDNA.

So, how are matches determined?

Matching

First your DNA and that of another person are scanned for nearly identical seed sequences.

A minimum segment length of 6cM must be identified for further match processing to occur. Anything below 6cM is discarded at this point.

The match is then further evaluated to see if the seed match is of a high enough quality that it should be perfected and should count as a match. Other segments continue to be evaluated as well. If the total matching segment(s) is 8 total cM or greater, it’s considered a valid match. MyHeritage has taken the position that they would rather give you a few accidental false matches than to miss good matches. I appreciate that position.

Window cleaning is how they refer to the process of removing pileup regions known to occur in the human genome. This is NOT the same as Ancestry’s routine that removes areas they determine to be “too matchy” for you individually.

The difference is that in humans, for example, there is a segment of chromosome 6 where, for some reason, almost all humans match. Matching across that segment is not informative for genetic genealogy, so that region along with several others similar in nature are removed. At Ancestry, those genome-wide pileup segments are removed, along with other regions where Ancestry decides that you personally have too many matches. The problem is that for me, these “too matchy” segments are many of my Acadian matches. Acadians are endogamous, so lots of them match each other because as a small intermarried population, they share a great deal of the same DNA. However, to me, because I have one great-grandfather that’s Acadian, that “too matchy” information IS valuable although I understand that it wouldn’t be for someone that is 100% Acadian or Jewish.

In situations such as Ashkenazi Jewish matching, which is highly endogamous, MyHeritage uses a higher matching threshold. Otherwise every Ashkenazi person would match every other Ashkenazi person because they all descend from a small founder population, and for genealogy, that’s not useful.

The last step in processing matches is to establish the confidence level that the match is accurately predicted at the correct level – meaning the relationship range based on the amount of matching DNA and other criteria.

For example, does this match cluster with other proven matches of the same known relationship level?

From several confidence ascertainment steps, a confidence score is assigned to the predicted relationship.

Of course, you as a customer see none of this background processing, just the fact that you do match, the size of the match and the confidence score. That’s what genealogists need!

Matching Versus Triangulation Thresholds

Confusion exists about matching thresholds versus triangulation thresholds.

While any single segment must be over 6 cM in length for the matching process to begin, the actual match threshold at MyHeritage is a total of 8 cM.

I took a look at my lowest match at MyHeritage.

I have two segments, one 6.1 cM segment, and one 6 cM segment that match. It would appear that if I only had one 6 cM segment, it would not show as a match because I didn’t have the minimum 8 cM total.

Triangulation Threshold

However, after you pass that matching criteria and move on to triangulation with a matching individual, you have the option of selecting the triangulation threshold, which is not the same thing as the match threshold. The match threshold does not change, but you can change the triangulation threshold from 2 cM to 8 cM and selections in-between.

In the example below, I’m comparing myself against two known relatives.

You won’t be shown any matches below the 6 cM individual segment threshold, BUT you can view triangulated segments of different sizes. This is because matching segments often don’t line up exactly and the triangulated overlap between several individuals may be very small, but may still be useful information.

Flying your mouse over the location in the bubble, which is the triangulated segment, tells you the size of the triangulated portion. If you selected the 2 cM triangulation, you would see smaller triangulated portions of matches.

Closing Session

The conference was closed by Aaron Godfrey, a super-nice MyHeritage employee from the UK. The closing session is worth watching on the recorded livestream when it becomes available, in part because there are feel good moments.

However, the piece of information I was looking for was whether there will be a MyHeritage LIVE conference in 2019, and if so, where.

I asked Gilad afterwards and he said that they will be evaluating the feedback from attendees and others when making that decision.

So, if you attended or joined the livestream sessions and found value, please let MyHeritage know so that they can factor your feedback onto their decision. If there are topics you’d like to see as sessions, I’m sure they’d love to hear about that too. Me, I’m always voting for more DNA😊

I hope to hear about MyHeritage LIVE 2019, and I’m voting for any of the following locations:

  • Australia
  • New Zealand
  • Israel
  • Germany
  • Switzerland

What do you think?

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Disclosure

I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

DNA Purchases and Free Transfers

Genealogy Services

Genealogy Research