DNA: In Search of…Signs of Endogamy

This is the fourth in our series of articles about searching for unknown close family members, specifically; parents, grandparents, or siblings. However, these same techniques can be applied by genealogists to ancestors further back in time as well.

In this article, we discuss endogamy – how to determine if you have it, from what population, and how to follow the road signs.

After introductions, we will be covering the following topics:

  • Pedigree collapse and endogamy
  • Endogamous groups
  • The challenge(s) of endogamy
  • Endogamy and unknown close relatives (parents, grandparents)
  • Ethnicity and Populations
  • Matches
  • AutoClusters
  • Endogamous Relationships
  • Endogamous DNA Segments
  • “Are Your Parents Related?” Tool
  • Surnames
  • Projects
  • Locations
  • Y DNA, Mitochondrial DNA, and Endogamy
  • Endogamy Tools Summary Tables
    • Summary of Endogamy Tools by Vendor
    • Summary of Endogamous Populations Identified by Each Tool
    • Summary of Tools to Assist People Seeking Unknown Parents and Grandparents

What Is Endogamy and Why Does It Matter?

Endogamy occurs when a group or population of people intermarry among themselves for an extended period of time, without the introduction of many or any people from outside of that population.

The effect of this continual intermarriage is that the founders’ DNA simply gets passed around and around, eventually in small segments.

That happens because there is no “other” DNA to draw from within the population. Knowing or determining that you have endogamy helps make sense of DNA matching patterns, and those patterns can lead you to unknown relatives, both close and distant.

This Article

This article serves two purposes.

  • This article is educational and relevant for all researchers. We discuss endogamy using multiple tools and examples from known endogamous people and populations.
  • In order to be able to discern endogamy when we don’t know who our parents or grandparents are, we need to know what signs and signals to look for, and why, which is based on what endogamy looks like in people who know their heritage.

There’s no crystal ball – no definitive “one-way” arrow, but there are a series of indications that suggest endogamy.

Depending on the endogamous population you’re dealing with, those signs aren’t always the same.

If you’re sighing now, I understand – but that’s exactly WHY I wrote this article.

We’re covering a lot of ground, but these road markers are invaluable diagnostic tools.

I’ve previously written about endogamy in the articles:

Let’s start with definitions.

Pedigree Collapse and Endogamy

Pedigree collapse isn’t the same as endogamy. Pedigree collapse is when you have ancestors that repeat in your tree.

In this example, the parents of our DNA tester are first cousins, which means the tester shares great-grandparents on both sides and, of course, the same ancestors from there on back in their tree.

This also means they share more of those ancestors’ DNA than they would normally share.

John Smith and Mary Johnson are both in the tree twice, in the same position as great-grandparents. Normally, Tester Smith would carry approximately 12.5% of each of his great-grandparents’ DNA, assuming for illustration purposes that exactly 50% of each ancestor’s DNA is passed in each generation. In this case, due to pedigree collapse, 25% of Tester Smith’s DNA descends from John Smith, and another 25% descends from Mary Johnson, double what it would normally be. 25% is the amount of DNA contribution normally inherited from grandparents, not great-grandparents.

While we may find first cousin marriages a bit eyebrow-raising today, they were quite common in the past. Both laws and customs varied with the country, time, social norms, and religion.

Pedigree Collapse and Endogamy is NOT the Same

You might think that pedigree collapse and endogamy is one and the same, but there’s a difference. Pedigree collapse can lead to endogamy, but it takes more than one instance of pedigree collapse to morph into endogamy within a population. Population is the key word for endogamy.

The main difference is that pedigree collapse occurs with known ancestors in more recent generations for one person, while endogamy is longer-term and systemic in a group of people.

Picture a group of people, all descended from Tester Smith’s great-grandparents intermarrying. Now you have the beginnings of endogamy. A couple hundred or a few hundred years later, you have true endogamy.

In other words, endogamy is pedigree collapse on a larger scale – think of a village or a church.

My ancestors’ village of Schnait, in Germany, is shown above in 1685. One church and maybe 30 or 40 homes. According to church and other records, the same families had inhabited this village, and region, for generations. It’s a sure bet that both pedigree collapse and endogamy existed in this small community.

If pedigree collapse happens over and over again because there are no other people within the community to marry, then you have endogamy. In other words, with endogamy, you assuredly DO have historical pedigree collapse, generally back in time, often before you can identify those specific ancestors – because everyone descends from the same set of founders.

Endogamy Doesn’t Necessarily Indicate Recent Pedigree Collapse

With deep, historic endogamy, you don’t necessarily have recent pedigree collapse, and in fact, many people do not. Jewish people are a good example of this phenomenon. They shared ancestors for hundreds or thousands of years, depending on which group we are referring to, but in recent, known, generations, many Jewish people aren’t related. Still, their DNA often matches each other.

The good news is that there are telltale signs and signals of endogamy.

The bad news is that not all of these are obvious, meaning as an aid to people seeking clues about unknown close relatives, and other “signs” aren’t what they are believed to be.

Let’s step through each endogamy identifier, or “hint,” and then we will review how we can best utilize this information.

First, let’s take a look at groups that are considered to be endogamous.

Endogamous Groups

Jewish PeopleSpecifically groups that were isolated from other groups of Jewish (and other) people; Ashkenazi (Germany, Northern France, and diaspora), Sephardic (Spanish, Iberia, and diaspora), Mizrahi (Israel, Middle Eastern, and diaspora,) Ethiopian Jews, and possibly Jews from other locations such as Mountain Jews from Kazakhstan and the Caucasus.

AcadiansDescendants of about 60 French families who settled in “Acadia” beginning about 1604, primarily on the island of Nova Scotia, and intermarried among themselves and with the Mi’kmaq people. Expelled by the English in 1755, they were scattered in groups to various diasporic regions where they continued to intermarry and where their descendants are found today. Some Acadians became the Cajuns of Louisiana.

Anabaptist Protestant FaithsAmish, Mennonite, and Brethren (Dunkards) and their offshoots are Protestant religious sects founded in Europe in the 14th, 15th, and 16th centuries on the principle of baptizing only adults or people who are old enough to choose to follow the faith, or rebaptizing people who had been previously baptized as children. These Anabaptist faiths tend to marry within their own group or church and often expel those who marry outside of the faith. Many emigrated to the American colonies and elsewhere, seeking religious freedom. Occasionally those groups would locate in close proximity and intermarry, but not marry outside of other Anabaptist denominations.

Native American (Indigenous) People – all indigenous peoples found in North and South America before European colonization descended from a small number of original founders who probably arrived at multiple times.

Indigenous Pacific Islanders – Including indigenous peoples of Australia, New Zealand, and Hawaii prior to colonization. They are probably equally as endogamous as Native American people, but I don’t have specific examples to share.

Villages – European or other villages with little inflow or whose residents were restricted from leaving over hundreds of years.

Other groups may have significant multiple lines of pedigree collapse and therefore become endogamous over time. Some people from Newfoundland, French Canadians, and Mormons (Church of Jesus Christ of Latter-Day Saints) come to mind.

Endogamy is a process that occurs over time.

Endogamy and Unknown Relatives

If you know who your relatives are, you may already know you’re from an endogamous population, but if you’re searching for close relatives, it’s helpful to be able to determine if you have endogamous heritage, at least in recent generations.

If you know nothing about either parent, some of these tools won’t help you, at least not initially, but others will. However, as you add to your knowledge base, the other tools will become more useful.

If you know the identity of one parent, this process becomes at least somewhat easier.

In future articles, we will search specifically for parents and each of your four grandparents. In this article, I’ll review each of the diagnostic tools and techniques you can use to determine if you have endogamy, and perhaps pinpoint the source.

The Challenge

People with endogamous heritage are related in multiple, unknown ways, over many generations. They may also be related in known ways in recent generations.

If both of your parents share the SAME endogamous culture or group of relatives:

  • You may have significantly more autosomal DNA matches than people without endogamy, unless that group of people is under-sampled. Jewish people have significantly more matches, but Native people have fewer due to under-sampling.
  • You may experience a higher-than-normal cM (centiMorgan) total for estimated relationships, especially more distant relationships, 3C and beyond.
  • You will have many matches related to you on both your maternal and paternal sides.
  • Parts of your autosomal DNA will be the same on both your mother’s and father’s sides, meaning your DNA will be fully identical in some locations. (I’ll explain more in a minute.)

If either (or both) of your parents are from an endogamous population, you:

  • Will, in some cases, carry identifying Y and mitochondrial DNA that points to a specific endogamous group. This is true for Native people, can be true for Jewish people and Pacific Islanders, but is not true for Anabaptist people.

One Size Does NOT Fit All

Please note that there is no “one size fits all.”

Each or any of these tools may provide relevant hints, depending on:

  • Your heritage
  • How many other people have tested from the relevant population group
  • How many close or distant relatives have tested
  • If your parents share the same heritage
  • Your unique DNA inheritance pattern
  • If your parents, individually, were fully endogamous or only partly endogamous, and how far back generationally that endogamy occurred

For example, in my own genealogy, my maternal grandmother’s father was Acadian on his father’s side. While I’m not fully endogamous, I have significantly more matches through that line proportionally than on my other lines.

I have Brethren endogamy on my mother’s side via her paternal grandmother.

Endogamous ancestors are shown with red stars on my mother’s pedigree chart, above. However, please note that her maternal and paternal endogamous ancestors are not from the same endogamous population.

However, I STILL have fewer matches on my mother’s side in total than on my father’s side because my mother has recent Dutch and recent German immigrants which reduces her total number of matches. Neither of those lines have had as much time to produce descendants in the US, and Europe is under-sampled when compared with the US where more people tend to take DNA tests because they are searching for where they came from.

My father’s ancestors have been in the US since it was a British Colony, and I have many more cousins who have tested on his side than mother’s.

If you looked at my pedigree chart and thought to yourself, “that’s messy,” you’d be right.

The “endogamy means more matches” axiom does not hold true for me, comparatively, between my parents – in part because my mother’s German and Dutch lines are such recent immigrants.

The number of matches alone isn’t going to tell this story.

We are going to need to look at several pieces and parts for more information. Let’s start with ethnicity.

Ethnicity and Populations

Ethnicity can be a double-edged sword. It can tell you exactly nothing you couldn’t discern by looking in the mirror, or, conversely, it can be a wealth of information.

Ethnicity reveals the parts of the world where your ancestors originated. When searching for recent ancestors, you’re most interested in majority ethnicity, meaning the 50% of your DNA that you received from each of your parents.

Ethnicity results at each vendor are easy to find and relatively easy to understand.

This individual at FamilyTreeDNA is 100% Ashkenazi Jewish.

If they were 50% Jewish, we could then estimate, and that’s an important word, that either one of their parents was fully Jewish, and not the other, or that two of their grandparents were Jewish, although not necessarily on the same side.

On the other hand, my mother’s ethnicity, shown below, has nothing remarkable that would point to any majority endogamous population, yet she has two.

The only hint of endogamy from ethnicity would be her ~1% Americas, and that isn’t relevant for finding close relatives. However, minority ancestry is very relevant for identifying Native ancestors, which I wrote about, here.

You can correlate or track your ethnicity segments to specific ancestors, which I discussed in the article, Native American & Minority Ancestors Identified Using DNAPainter Plus Ethnicity Segments, here.

Since I wrote that article, FamilyTreeDNA has added the feature of ethnicity or population Chromosome Painting, based on where each of your populations fall on your chromosomes.

In this example on chromosome 1, I have European ancestry (blue,) except for the pink Native segment, which occurs on the following segment in the same location on my mother’s chromosome 1 as well.

Both 23andMe, and FamilyTreeDNA provide chromosome painting AND the associated segment information so you can identify the relevant ancestors.

Ancestry is in the process of rolling out an ethnicity painting feature, BUT, it has no segment or associated matching information. While it’s interesting eye candy, it’s not terribly useful beyond the ethnicity information that Ancestry already provides. However, Jonny Perl at DNAPainter has devised a way to estimate Ancestry’s start and stop locations, here. Way to go Jonny!

Now all you need to do is convince your Ancestry matches to upload their DNA file to one of the three databases, FamilyTreeDNA, MyHeritage, and GEDMatch, that accept transfers, aka uploads. This allows matching with segment data so that you can identify who matches you on that segment, track your ancestors, and paint your ancestral segments at DNAPainter.

I provided step-by-step instructions, here, for downloading your raw DNA file from each vendor in order to upload the file to another vendor.

Ethnicity Sides

Three of the four DNA testing vendors, 23andMe, FamilyTreeDNA, and recently, Ancestry, attempt to phase your ethnicity DNA, meaning to assign it to one parental “side” or the other – both in total and on each chromosome.

Here’s Ancestry’s SideView, where your DNA is estimated to belong to parent 1 and parent 2. I detailed how to determine which side is which, here, and while that article was written specifically pertaining to Ancestry’s SideView, the technique is relevant for all the vendors who attempt to divide your DNA into parents, a technique known as phasing.

I say “attempt” because phasing may or may not be accurate, meaning the top chromosome may not always be parent 1, and the bottom chromosome may not always be chromosome 2.

Here’s an example at 23andMe.

See the two yellow segments. They are both assigned as Native. I happen to know one is from the mother and one is from the father, yet they are both displayed on the “top” chromosome, which one would interpret to be the same parent.

I am absolutely positive this is not the case because this is a close family member, and I have the DNA of the parent who contributed the Native segment on chromosome 1, on the top chromosome. That parent does not have a Native segment on chromosome 2 to contribute. So that Native segment had to be contributed by the other parent, but it’s also shown on the top chromosome.

The DNA segments circled in purple belong together on the same “side” and were contributed to the tester by the same parent. The Native segment on chromosome 2 abuts a purple African segment, suggesting perhaps that the ancestor who contributed that segment was mixed between those ethnicities. In the US, that suggests enslavement.

The other African segments, circled, are shown on the second chromosome in each pair.

To be clear, parent 1 is not assigned by the vendors to either mother or father and will differ by person. Your parent 1, or the parent on the top chromosome may be your mother and another person’s parent 1 may be their father.

As shown in this example, parents can vary by chromosome, a phenomenon known as “strand swap.” Occasionally, the DNA can even be swapped within a chromosome assignment.

You can, however, get an idea of the division of your DNA at any specific location. As shown above, you can only have a maximum of two populations of DNA on any one chromosome location.

In our example above, this person’s majority ancestry is European (blue.) On each chromosome where we find a minority segment, the opposite chromosome in the same location is European, meaning blue.

Let’s look at another example.

At FamilyTreeDNA, the person whose ethnicity painting is shown below has a Native American (pink) ancestor on their father’s side. FamilyTreeDNA has correctly phased or identified their Native segments as all belonging to the second chromosome in each pair.

Looking at chromosome 18, for example, most of their father’s chromosome is Native American (pink). The other parent’s chromosome is European (dark blue) at those same locations.

If one of the parents was of one ethnicity, and the other parent is a completely different ethnicity, then one bar of each chromosome would be all pink, for example, and one would be entirely blue, representing the other ethnicity.

Phasing ethnicity or populations to maternal and paternal sides is not foolproof, and each chromosome is phased individually.

Ethnicity can, in some cases, give you a really good idea of what you’re dealing with in terms of heritage and endogamy.

If someone had an Ashkenazi Jewish father and European mother, for example, one copy of each chromosome would be yellow (Ashkenazi Jewish), and one would be blue (European.)

However, if each of their parents were half European Jewish and half European (not Jewish), then their different colored segments would be scattered across their entire set of chromosomes.

In this case, both of the tester’s parents are mixed – European Jewish (green) and Western Europe (blue.) We know both parents are admixed from the same two populations because in some locations, both parents contributed blue (Western Europe), and in other locations, both contributed Jewish (green) segments.

Both MyHeritage and Ancestry provide a secondary tool that’s connected to ethnicity, but different and generally in more recent times.

Ancestry’s DNA Communities

While your ethnicity may not point to anything terribly exciting in terms of endogamy, Genetic Communities might. Ancestry says that a DNA Community is a group of people who share DNA because their relatives recently lived in the same place at the same time, and that communities are much smaller than ethnicity regions and reach back only about 50-300 years.

Based on the ancestors’ locations in the trees of me and my matches, Ancestry has determined that I’m connected to two communities. In my case, the blue group is clearly my father’s line. The orange group could be either parent, or even a combination of both.

My endogamous Brethren could be showing up in Maryland, Pennsylvania, and Ohio, but it’s uncertain, in part, because my father’s ancestral lines are found in Virginia, West Virginia, and Maryland too.

These aren’t useful for me, but they may be more useful for fully endogamous people, especially in conjunction with ethnicity.

My Acadian cousin’s European ethnicity isn’t informative.

However, viewing his DNA Communities puts his French heritage into perspective, especially combined with his match surnames.

I wrote about DNA Communities when it was introduced with the name Genetic Communities, here.

MyHeritage’s Genetic Groups

MyHeritage also provides a similar feature that shows where my matches’ ancestors lived in the same locations as mine.

One difference, though, is that testers can adjust their ethnicity results confidence level from high, above, to low, below where one of my Genetic Groups overlaps my ethnicity in the Netherlands.

You can also sort your matches by Genetic Groups.

The results show you not only who is in the group, but how many of your matches are in that group too, which provides perspective.

I wrote about Genetic Groups, here.

Next, let’s look at how endogamy affects your matches.

Matches

The number of matches that a person has who is from an entirely endogamous community and a person with no endogamy may be quite different.

FamilyTreeDNA provides a Family Matching feature that triangulates your matches and assigns them to your paternal or maternal side by using known matches that you have linked to their profile cards in your tree. You must link people for the Family Matching feature known as “bucketing” to be enabled.

The people you link are then processed for shared matches on the same chromosome segment(s). Triangulated individuals are then deposited in your maternal, paternal, and both buckets.

Obviously, your two parents are the best people to link, but if they haven’t tested (or uploaded their DNA file from another vendor) and you have other known relatives, link them using the Family Tree tab at the top of your personal page.

I uploaded my Ancestry V4 kit to use as an example for linking. Let’s pretend that’s my sister. If I had not already linked my Ancestry V4 kit to “my sister’s” profile card, I’d want to do that and link other known individuals the same way. Just drag and drop the match to the correct profile card.

Note that a full or half sibling will be listed as such at FamilyTreeDNA, but an identical twin will show as a potential parent/child match to you. You’re much more likely to find a parent than an identical twin, but just be aware.

I’ve created a table of FamilyTreeDNA bucketed match results, by category, comparing the number of matches in endogamous categories with non-endogamous.

Total Matches Maternal Matches Paternal Matches Both % Both % DNA Unassigned
100% Jewish 34,637 11,329 10,416 4,806 13.9 23.3
100% Jewish 32,973 10,700 9,858 4,606 14 23.7
100% Jewish 32,255 9,060 10,970 3,892 12 25.8
75% Jewish 24,232 11,846 Only mother linked Only mother linked Only mother linked
100% Acadian 8093 3826 2299 1062 13 11
100% Acadian 7828 3763 1825 923 11.8 17
Not Endogamous 6760 3845 1909 13 0.19 14.5
Not Endogamous 7723 1470 3317 6 0.08 38
100% Native American 1,115 Unlinked Unlinked Unlinked
100% Native American 885 290 Unknown Can’t calculate without at least one link on both sides

The 100% Jewish, Acadian, and Not Endogamous testers both have linked their parents, so their matches, if valid (meaning not identical by chance, which I discussed here,) will match them plus one or the other parent.

One person is 75% Jewish and has only linked their Jewish mother.

The Native people have not tested their parents, and the first Native person has not linked anyone in their tree. The second Native person has only linked a few maternal matches, but their mother has not tested. They are seeking their father.

It’s very difficult to find people who are fully Native as testers. Furthermore, Native people are under-sampled. If anyone knows of fully Native (or other endogamous) people who have tested and linked their parents or known relatives in their trees, and will allow me to use their total match numbers anonymously, please let me know.

As you can see, Jewish, Acadian, and Native people are 100% endogamous, but many more Jewish people than Native people have tested, so you CAN’T judge endogamy by the total number of matches alone.

In fact, in order:

  • Fully Jewish testers have about 4-5 times as many matches as the Acadian and Non-endogamous testers
  • Acadian and Non-endogamous testers have about 5-6 times as many matches as the Native American testers
  • Fully Jewish people have about 30 times more matches than the Native American testers

If a person’s endogamy with a particular population is only on their maternal or paternal side, they won’t have a significant number of people related to both sides, meaning few people will fall into the “Both” bucket. People that will always be found in the ”Both” bucket are full siblings and their descendants, along with descendants of the tester, assuming their match is linked to their profiles in the tester’s tree.

In the case of our Jewish testers, you can easily see that the “Both” bucket is very high. The Acadians are also higher than one would reasonably expect without endogamy. A non-endogamous person might have a few matches on both sides, assuming the parents are not related to each other.

A high number of “Both” matches is a very good indicator of endogamy within the same population on both parents’ sides.

The percentage of people who are assigned to the “Both” bucket is between 11% and 14% in the endogamous groups, and less than 1% in the non-endogamous group, so statistically not relevant.

As demonstrated by the Native people compared to the Jewish testers, the total number of matches can be deceiving.

However, being related to both parents, as indicated by the “Both” bucket, unless you have pedigree collapse, is a good indicator of endogamy.

Of course, if you don’t know who your relatives are, you can’t link them in your tree, so this type of “hunt” won’t generally help people seeking their close family members.

However, you may notice that you’re matching people PLUS both of their parents. If that’s the case, start asking questions of those matches about their heritage.

A very high number of total matches, as compared to non-endogamous people, combined with some other hints might well point to Jewish heritage.

I included the % DNA Unassigned category because this category, when both parents are linked, is the percentage of matches by chance, meaning the match doesn’t match either of the tester’s parents. All of the people with people listed in “Both” categories have linked both of their parents, not just maternal and paternal relatives.

Matching Location at MyHeritage

MyHeritage provides a matching function by location. Please note that it’s the location of the tester, but that may still be quite useful.

The locations are shown in the most-matches to least-matches order. Clicking on the location shows the people who match you who are from that location. This would be the most useful in situations where recent immigration has occurred. In my case, my great-grandfather from the Netherlands arrived in the 1860s, and my German ancestors arrived in the 1850s. Neither of those groups are endogamous, though, unless it would be on a village level.

AutoClusters

Let’s shift to Genetic Affairs, a third-party tool available to everyone.

Using their AutoCluster function, Genetic Affairs clusters your matches together who match both each other and you.

This is an example of the first few clusters in my AutoCluster. You can see that I have several colored clusters of various sizes, but none are huge.

Compare that to the following endogamous cluster, sample courtesy of EJ Blom at Genetic Affairs.

If your AutoCluster at Genetic Affairs looks something like this, a huge orange blob in the upper left hand corner, you’re dealing with endogamy.

Please also note that the size of your cluster is also a function of both the number of testers and the match threshold you select. I always begin by using the defaults. I wrote about using Genetic Affairs, here.

If you tested at or transferred to MyHeritage, they too license AutoClusters, but have optimized the algorithm to tease out endogamous matches so that their Jewish customers, in particular, don’t wind up with a huge orange block of interrelated people.

You won’t see the “endogamy signature” huge cluster in the corner, so you’re less likely to be able to discern endogamy from a MyHeritage cluster alone.

The commonality between these Jewish clusters at MyHeritage is that they all tend to be rather uniform in size and small, with lots of grey connecting almost all the blocks.

Grey cells indicate people who match people in two colored groups. In other words, there is often no clear division in clusters between the mother’s side and the father’s side in Jewish clusters.

In non-endogamous situations, even if you can’t identify the parents, the clusters should still fall into two sides, meaning a group of clusters for each parent’s side that are not related to each other.

You can read more about Genetic Affairs clusters and their tools, here. DNAGedcom.com also provides a clustering tool.

Endogamous Relationships

Endogamous estimated relationships are sometimes high. Please note the word, “sometimes.”

Using the Shared cM Project tool relationship chart, here, at DNAPainter, people with heavy endogamy will discover that estimated relationships MAY be on the high side, or the relationships may, perhaps, be estimated too “close” in time. That’s especially true for more distant relationships, but surprisingly, it’s not always true. The randomness of inheritance still comes into play, and so do potential unknown relatives. Hence, the words “may” are bolded and underscored.

Unfortunately, it’s often stated as “conventional wisdom” that Jewish matches are “always” high, and first cousins appear as siblings. Let’s see what the actual data says.

At DNAPainter, you can either enter the amount of shared DNA (cM), or the percent of shared DNA, or just use the chart provided.

I’ve assembled a compilation of close relationships in kits that I have access to or from people who were generous enough to share their results for this article.

I’ve used Jewish results, which is a highly endogamous population, compared with non-endogamous testers.

The “Jewish Actual” column reports the total amount of shared DNA with that person. In other words, someone to their grandparent. The Average Range is the average plus the range from DNAPainter. The Percent Difference is the % difference between the actual number and the DNAPainter average.

You’ll see fully Jewish testers, at left, matching with their family members, and a Non-endogamous person, at right, matching with their same relative.

Relationship Jewish Actual Percent Difference than Average Average -Range Non-endogamous Actual Percent Difference than Average
Grandparent 2141 22 1754 (984-2482) 1742 <1 lower
Grandparent 1902 8.5 1754 (984-2482) 1973 12
Sibling 3039 16 2613 (1613-3488) 2515 3.5 lower
Sibling 2724 4 2613 (1613-3488) 2761 5.5
Half-Sibling 2184 24 1759 (1160-2436) 2127 21
Half-Sibling 2128 21 1759 (1160-2436) 2352 34
Aunt/Uncle 2066 18.5 1741 (1201-2282) 1849 6
Aunt/Uncle 2031 16.5 1741 (1201-2282) 2097 20
1C 1119 29 866 (396-1397) 959 11
1C 909 5 866 (396-1397) 789 9 lower
1C1R 514 19 433 (102-980) 467 8
1C1R 459 6 433 (102-980) 395 9 lower

These totals are from FamilyTreeDNA except one from GEDMatch (one Jewish Half-sibling).

Totals may vary by vendor, even when matching with the same person. 23andMe includes the X segments in the total cMs and also counts fully identical segments twice. MyHeritage imputation seems to err on the generous side.

However, in these dozen examples:

  • You can see that the Jewish actual amount of DNA shared is always more than the average in the estimate.
  • The red means the overage is more than 100 cM larger.
  • The percentage difference is probably more meaningful because 100 cM is a smaller percentage of a 1754 grandparent connection than compared to a 433 cM 1C1R.

However, you can’t tell anything about endogamy by just looking at any one sample, because:

  • Some of the Non-Endogamous matches are high too. That’s just the way of random inheritance.
  • All of the actual Jewish match numbers are within the published ranges, but on the high side.

Furthermore, it can get more complex.

Half Endogamous

I requested assistance from Jewish genealogy researchers, and a lovely lady, Sharon, reached out, compiled her segment information, and shared it with me, granting permission to share with you. A HUGE thank you to Sharon!

Sharon is half-Jewish via one parent, and her half-sibling is fully Jewish. Their half-sibling match to each other at Ancestry is 1756 cM with a longest segment of 164 cM.

How does Jewish matching vary if you’re half-Jewish versus fully Jewish? Let’s look at 21 people who match both Sharon and her fully Jewish half-sibling.

Sharon shared the differences in 21 known Jewish matches with her and her half-sibling. I’ve added the Relationship Estimate Range from DNAPainter and colorized the highest of the two matches in yellow. Bolding in the total cM column shows a value above the average range for that relationship.

Total Matching cMs is on the left, with Longest Segment on the right.

While this is clearly not a scientific study, it is a representative sample.

The fully Jewish sibling carries more Jewish DNA, which is available for other Jewish matches to match as a function of endogamy (identical by chance/population), so I would have expected the fully Jewish sibling to match most if not all Jewish testers at a higher level than the half-Jewish sibling.

However, that’s not universally what we see.

The fully Jewish sibling is not always the sibling with the highest number of matches to the other Jewish testers, although the half-Jewish tester has the larger “Longest Segment” more often than not.

Approximately two-thirds of the time (13/21), the fully Jewish person does have a higher total matching cM, but about one-third of the time (8/21), the half-Jewish sibling has a higher matching cM.

About one-fourth of the time (5/21), the fully Jewish sibling has the longest matching segment, and about two-thirds of the time (13/21), the half-Jewish sibling does. In three cases, or about 14% of the time, the longest segment is equal which may indicate that it’s the same segment.

Because of endogamy, Jewish matches are more likely to have:

  • Larger than average total cM for the specific relationship
  • More and smaller matching segments

However, as we have seen, neither of those are definitive, nor always true. Jewish matches and relationships are not always overestimated.

Ancestry and Timber

Please note that Ancestry downweights some matches by removing some segments using their Timber algorithm. Based on my matches and other accounts that I manage, Ancestry does not downweight in the 2-3rd cousin category, which is 90 cM and above, but they do begin downweighting in the 3-4th cousin category, below 90 cM, where my “Extended Family” category begins.

If you’ve tested at Ancestry, you can check for yourself.

By clicking on the amount of DNA you share with your match on your match list at Ancestry, shown above, you will be taken to another page where you will be able to view the unweighted shared DNA with that match, meaning the amount of DNA shared before the downweighting and removal of some segments, shown below.

Given the downweighting, and the information in the spreadsheet provided by Sharon, it doesn’t appear that any of those matches would have been in a category to be downweighted.

Therefore, for these and other close matches, Timber wouldn’t be a factor, but would potentially be in more distant matches.

Endogamous Segments

Endogamous matches tend to have smaller and more segments. Small amounts of matching DNA tend to skew the total DNA cM upwards.

How and why does this happen?

Ancestral DNA from further back in time tends to be broken into smaller segments.

Sometimes, especially in endogamous situations, two smaller segments, at one time separated from each other, manage to join back together again and form a match, but the match is only due to ancestral segments – not because of a recent ancestor.

Please note that different vendors have different minimum matching cM thresholds, so smaller matches may not be available at all vendors. Remember that factors like Timber and imputation can affect matching as well.

Let’s take a look at an example. I’ve created a chart where two ancestors have their blue and pink DNA broken into 4 cM segments.

They have children, a blue child and a pink child, and the two children, shown above, each inherited the same blue 4 cM segment and the same pink 4 cM segment from their respective parents. The other unlabeled pink and blue segments are not inherited by these two children, so those unlabeled segments are irrelevant in this example.

The parents may have had other children who inherited those same 4 cM labeled pink and blue segments as well, and if not, the parents’ siblings were probably passing at least some of the same DNA down to their descendants too.

The blue and pink children had children, and their children had children – for several generations.

Time passed, and their descendants became an endogamous community. Those pink and blue 4 cM segments may at some time be lost during recombination in the descendants of each of their children, shown by “Lost pink” and “Lost blue.”

However, because there is only a very limited amount of DNA within the endogamous community, their descendants may regain those same segments again from their “other parent” during recombination, downstream.

In each generation, the DNA of the descendant carrying the original blue or pink DNA segment is recombined with their partner. Given that the partners are both members of the same endogamous community, the two people may have the same pink and/or blue DNA segments. If one parent doesn’t carry the pink 4 cM segment, for example, their offspring may receive that ancestral pink segment from the other parent.

They could potentially, and sometimes do, receive that ancestral segment from both parents.

In our example, the descendants of the blue child, at left, lost the pink 4 cM segment in generation 3, but a few generations later, in generation 11, that descendant child inherited that same pink 4 cM segment from their other parent. Therefore, both the 4 cM blue and 4 cM pink segments are now available to be inherited by the descendants in that line. I’ve shown the opposite scenario in the generational inheritance at right where the blue segment is lost and regained.

Once rejoined, that pink and blue segment can be passed along together for generations.

The important part, though, is that once those two segments butt up against each other again during recombination, they aren’t just two separate 4 cM segments, but one segment that is 8 cM long – that is now equal to or above the vendors’ matching threshold.

This is why people descended from endogamous populations often have the following matching characteristics:

  • More matches
  • Many smaller segment matches
  • Their total cM is often broken into more, smaller segments

What does more, smaller segments, look like, exactly?

More, Smaller Segments

All of our vendors except Ancestry have a chromosome browser for their customers to compare their DNA to that of their matches visually.

Let’s take a look at some examples of what endogamous and non-endogamous matches look like.

For example, here’s a screen shot of a random Jewish second cousin match – 298 cM total, divided into 12 segments, with a longest segment of 58 cM,

A second Jewish 2C with 323 cM total, across 19 segments, with a 69 cM longest block.

A fully Acadian 2C match with 600 cM total, across 27 segments, with a longest segment of 69 cM.

A second Acadian 2C with 332 cM total, across 20 segments, with a longest segment of 42 cM.

Next, a non-endogamous 2C match with 217 cM, across 7 segments, with a longest segment of 72 cM.

Here’s another non-endogamous 2C example, with 169 shared cM, across 6 segments, with a longest segment of 70 cM.

Here’s the second cousin data in a summary table. The take-away from this is the proportion of total segments

Tester Population Total cM Longest Block Total Segments
Jewish 2C 298 58 12
Jewish 2C 323 69 19
Acadian 2C 600 69 27
Acadian 2C 332 42 20
Non-endogamous 2C 217 72 7
Non-endogamous 2C 169 70 6

You can see more examples and comparisons between Native American, Jewish and non-endogamous DNA individuals in the article, Concepts – Endogamy and DNA Segments.

I suspect that a savvy mathematician could predict endogamy based on longest block and total segment information.

Lara Diamond, a mathematician, who writes at Lara’s Jewnealogy might be up for this challenge. She just published compiled matching and segment information in her Ashkenazic Shared DNA Survey Results for those who are interested. You can also contribute to Laura’s data, here.

Endogamy, Segments, and Distant Relationships

While not relevant to searching for close relatives, heavily endogamous matches 3C and more distant, to quote one of my Jewish friends, “dissolve into a quagmire of endogamy and are exceedingly difficult to unravel.”

In my own Acadian endogamous line, I often simply have to label them “Acadian” because the DNA tracks back to so many ancestors in different lines. In other words, I can’t tell which ancestor the match is actually pointing to because the same DNA segments or segments is/are carried by several ancestors and their descendants due to founder effect.

The difference with the Acadians is that we can actually identify many or most of them, at least at some point in time. As my cousin, Paul LeBlanc, once said, if you’re related to one Acadian, you’re related to all Acadians. Then he proceeded to tell me that he and I are related 137 different ways. My head hurts!

It’s no wonder that endogamy is incredibly difficult beyond the first few generations when it turns into something like multi-colored jello soup.

“Are Your Parents Related?” Tool

There’s another tool that you can utilize to determine if your parents are related to each other.

To determine if your parents are related to each other, you need to know about ROH, or Runs of Homozygosity (ROH).

ROH means that the DNA on both strands or copies of the same chromosome is identical.

For a few locations in a row, ROH can easily happen just by chance, but the longer the segment, the less likely that commonality occurs simply by chance.

The good news is that you don’t need to know the identity of either of your parents. You don’t need either of your parent’s DNA tests – just your own. You’ll need to upload your DNA file to GEDmatch, which is free.

Click on “Are your parents related?”

GEDMatch analyzes your DNA to see if any of your DNA, above a reasonable matching threshold, is identical on both strands, indicating that you inherited the exact same DNA from both of your parents.

A legitimate match, meaning one that’s not by chance, will include many contiguous matching locations, generally a minimum of 500 SNPs or locations in a row. GEDmatch’s minimum threshold for identifying identical ancestral DNA (ROH) is 200 cM.

Here’s my result, including the graphic for the first two chromosomes. Notice the tiny green bars that show identical by chance tiny sliver segments.

I have no significant identical DNA, meaning my parents are not related to each other.

Next, let’s look at an endogamous example where there are small, completely identical segments across a person’s chromosome

This person’s Acadian parents are related to each other, but distantly.

Next, let’s look at a Jewish person’s results.

You’ll notice larger green matching ROH, but not over 200 contiguous SNPs and 7 cM.

GEDMatch reports that this Jewish person’s parents are probably not related within recent generations, but it’s clear that they do share DNA in common.

People whose parents are distantly related have relatively small, scattered matching segments. However, if you’re seeing larger ROH segments that would be large enough to match in a genealogical setting, meaning multiple greater than 7 cM and 500 SNPs,, you may be dealing with a different type of situation where cousins have married in recent generations. The larger the matching segments, generally, the closer in time.

Blogger Kitty Cooper wrote an article, here, about discovering that your parents are related at the first cousin level, and what their GEDMatch “Are Your Parents Related” results look like.

Let’s look for more clues.

Surnames

There MAY be an endogamy clue in the surnames of the people you match.

Viewing surnames is easier if you download your match list, which you can do at every vendor except Ancestry. I’m not referring to the segment data, but the information about your matches themselves.

I provided instructions in the recent article, How to Download Your DNA Match Lists and Segment Files, here.

If you suspect endogamy for any reason, look at your closest matches and see if there is a discernable trend in the surnames, or locations, or any commonality between your matches to each other.

For example, Jewish, Acadian, and Native surnames may be recognizable, as may locations.

You can evaluate in either or both of two ways:

  • The surnames of your closest matches. Closest matches listed first will be your default match order.
  • Your most frequently occurring surnames, minus extremely common names like Smith, Jones, etc., unless they are also in your closest matches. To utilize this type of matching, sort the spreadsheet in surname order and then scan or count the number of people with each surname.

Here are some examples from our testers.

Jewish – Closest surname matches.

  • Roth
  • Weiss
  • Goldman
  • Schonwald
  • Levi
  • Cohen
  • Slavin
  • Goodman
  • Sender
  • Trebatch

Acadian – Closest surname matches.

  • Bergeron
  • Hebert
  • Bergeron
  • Marcum
  • Muise
  • Legere
  • Gaudet
  • Perry
  • Verlander
  • Trombley

Native American – Closest surname matches.

  • Ortega
  • Begay
  • Valentine
  • Hayes
  • Montoya
  • Sun Bear
  • Martin
  • Tsosie
  • Chiquito
  • Yazzie

You may recognize these categories of surnames immediately.

If not, Google is your friend. Eliminate common surnames, then Google for a few together at a time and see what emerges.

The most unusual surnames are likely your best bets.

Projects

Another way to get some idea of what groups people with these surnames might belong to is to enter the surname in the FamilyTreeDNA surname search.

Go to the main FamilyTreeDNA page, but DO NOT sign on.

Scroll down until you see this image.

Type the surname into the search box. You’ll see how many people have tested with that surname, along with projects where project administrators have included that surname indicating that the project may be of interest to at least some people with that surname.

Here’s a portion of the project list for Cohen, a traditional Jewish surname.

These results are for Muise, an Acadian surname.

Clicking through to relevant surname projects, and potentially contacting the volunteer project administrator can go a very long way in helping you gather and sift information. Clearly, they have an interest in this topic.

For example, here’s the Muise surname in the Acadian AmerIndian project. Two great hints here – Acadian heritage and Halifax, Nova Scotia.

Repeat for the balance of surnames on your list to look for commonalities, including locations on the public project pages.

Locations

Some of the vendor match files include location information. Each person on your match list will have the opportunity at the vendor where they tested to include location information in a variety of ways, either for their ancestors or themselves.

Where possible, it’s easiest to sort or scan the download file for this type of information.

Ancestry does not provide or facilitate a match list, but you can still create your own for your closest 20 or 30 matches in a spreadsheet.

MyHeritage provides common surname and ancestral location information for every match. How cool is that!

Y DNA, Mitochondrial DNA, and Endogamy

Haplogroups for both Y and mitochondrial DNA can indicate and sometimes confirm endogamy. In other cases, the haplogroup won’t help, but the matches and their location information just might.

FamilyTreeDNA is the only vendor that provides Y DNA and mitochondrial DNA tests that include highly granular haplogroups along with matches and additional tools.

23andMe provides high-level haplogroups which may or may not be adequate to pinpoint a haplogroup that indicates endogamy.

Of course, only males carry Y DNA that tracks to the direct paternal (surname) line, but everyone carries their mother’s mitochondrial DNA that represents their mother’s mother’s mother’s, or direct matrilineal line.

Some haplogroups are known to be closely associated with particular ethnicities or populations, like Native Americans, Pacific Islanders, and some Jewish people.

Haplogroups reach back in time before genealogy and can give us a sense of community that’s not available by either looking in the mirror or through traditional records.

This Native American man is a member of high-level haplogroup Q-M242. However, some men who carry this haplogroup are not Native, but are of European or Middle Eastern origin.

I entered the haplogroup in the FamilyTreeDNA Discover tool, which I wrote about, here.

Checking the information about this haplogroup reveals that their common ancestor descended from an Asian man about 30,000 years ago.

The migration path in the Americans explains why this person would have an endogamous heritage.

Our tester would receive a much more refined haplogroup if he upgraded to the Big Y test at FamilyTreeDNA, which would remove all doubt.

However, even without additional testing, information about his matches at FamilyTreeDNA may be very illuminating.

The Q-M242 Native man’s Y DNA matches men with more granular haplogroups, shown above, at left. On the Haplogroup Origins report, you can see that these people have all selected the “US (Native American)” country option.

Another useful tool would be to check the public Y haplotree, here, and the public mitochondrial tree here, for self-reported ancestor location information for a specific haplogroup.

Here’s an example of mitochondrial haplogroup A2 and a few subclades on the public mitochondrial tree. You can see that the haplogroup is found in Mexico, the US (Native,) Canada, and many additional Caribbean, South, and Central American countries.

Of course, Y DNA and mitochondrial DNA (mtDNA) tell a laser-focused story of one specific line, each. The great news, if you’re seeking information about your mother or father, the Y is your father’s direct paternal (surname) line, and mitochondrial is your mother’s direct matrilineal line.

Y and mitochondrial DNA results combined with ethnicity, autosomal matching, and the wide range of other tools that open doors, you will be able to reveal a great deal of information about whether you have endogamous heritage or not – and if so, from where.

I’ve provided a resource for stepping through and interpreting your Y DNA results, here, and mitochondrial DNA, here.

Discover for Y DNA Only

If you’re a female, you may feel left out of Y DNA testing and what it can tell you about your heritage. However, there’s a back door.

You can utilize the Y DNA haplogroups of your closest autosomal matches at both FamilyTreeDNA and 23andMe to reveal information

Haplogroup information is available in the download files for both vendors, in addition to the Family Finder table view, below, at FamilyTreeDNA, or on your individual matches profile cards at both 23andMe and FamilyTreeDNA.

You can enter any Y DNA haplogroup in the FamilyTreeDNA Discover tool, here.

You’ll be treated to:

  • Your Haplogroup Story – how many testers have this haplogroup (so far), where the haplogroup is from, and the haplogroup’s age. In this case, the haplogroup was born in the Netherlands about 250 years ago, give or take 200 years. I know that it was 1806 or earlier based on the common ancestor of the men who tested.
  • Country Frequency – heat map of where the haplogroup is found in the world.
  • Notable Connections – famous and infamous (this haplogroup’s closest notable person is Leo Tolstoy).
  • Migration Map – migration path out of Africa and through the rest of the world.
  • Ancient Connections – ancient burials. His closest ancient match is from about 1000 years ago in Ukraine. Their shared ancestor lived about 2000 years ago.
  • Suggested Projects – based on the surname, projects that other matches have joined, and haplogroups.
  • Scientific Details – age estimates, confidence intervals, graphs, and the mutations that define this haplogroup.

I wrote about the Discover tool in the article, FamilyTreeDNA DISCOVER Launches – Including Y DNA Haplogroup Ages.

Endogamy Tools Summary Tables

Endogamy is a tough nut sometimes, especially if you’re starting from scratch. In order to make this topic a bit easier and to create a reference tool for you, I’ve created three summary tables.

  • Various endogamy-related tools available at each vendor which will or may assist with evaluating endogamy
  • Tools and their ability to detect endogamy in different groups
  • Tools best suited to assist people seeking information about unknown parents or grandparents

Summary of Endogamy Tools by Vendor

Please note that GEDMatch is not a DNA testing vendor, but they accept uploads and do have some tools that the testing vendors do not.

 Tool 23andMe Ancestry FamilyTreeDNA MyHeritage GEDMatch
Ethnicity Yes Yes Yes Yes Use the vendors
Ethnicity Painting Yes + segments Yes, limited Yes + segments Yes
Ethnicity Phasing Yes Partial Yes No
DNA Communities No Yes No No
Genetic Groups No No No Yes
Family Matching aka Bucketing No No Yes No
Chromosome Browser Yes No Yes Yes Yes
AutoClusters Through Genetic Affairs No Through Genetic Affairs Yes, included Yes, with subscription
Match List Download Yes, restricted # of matches No Yes Yes Yes
Projects No No Yes No
Y DNA High-level haplogroup only No Yes, full haplogroup with Big Y, matching, tools, Discover No
Mitochondrial DNA High-level haplogroup only No Yes, full haplogroup with mtFull, matching, tools No
Public Y Tree No No Yes No
Public Mito Tree No No Yes No
Discover Y DNA – public No No Yes No
ROH No No No No Yes

Summary of Endogamous Populations Identified by Each Tool

The following chart provides a guideline for which tools are useful for the following types of endogamous groups. Bolded tools require that both parents be descended from the same endogamous group, but several other tools give more definitive results with higher amounts of endogamy.

Y and mitochondrial DNA testing are not affected by admixture, autosomal DNA or anything from the “other” parent.

Tool Jewish Acadian Anabaptist Native Other/General
Ethnicity Yes No No Yes Pacific Islander
Ethnicity Painting Yes No No Yes Pacific Islander
Ethnicity Phasing Yes, if different No No Yes, if different Pacific Islander, if different
DNA Communities Yes Possibly Possibly Yes Pacific Islander
Genetic Groups Yes Possibly Possibly Yes Pacific Islander
Family Matching aka Bucketing Yes Yes Possibly Yes Pacific Islander
Chromosome Browser Possibly Possibly Yes, once segments or ancestors identified Possibly Pacific Islander, possibly
Total Matches Yes, compared to non-endogamous No No No No, unknown
AutoClusters Yes Yes Uncertain, probably Yes Pacific Islander
Estimated Relationships High Not always Sometimes No Sometimes Uncertain, probably
Relationship Range High Possibly, sometimes Possibly Possibly Possibly Pacific Islander, possibly
More, Smaller Segments Yes Yes Probably Yes Pacific Islander, probably
Parents Related Some but minimal Possibly Uncertain Probably similar to Jewish Uncertain, Possibly
Surnames Probably Probably Probably Not Possibly Possibly
Locations Possibly Probably Probably Not Probably Probably Pacific Islander
Projects Probably Probably Possibly Possibly Probably Pacific Islander
Y DNA Yes, often Yes, often No Yes Pacific Islander
Mitochondrial DNA Yes, often Sometimes No Yes Pacific Islander
Y public tree Probably not alone No No Yes Pacific Islander
MtDNA public tree Probably not No No Yes Pacific Islander
Y DNA Discover Yes Possibly Probably not, maybe projects Yes Pacific Islander

Summary of Endogamy Tools to Assist People Seeking Unknown Parents and Grandparents

This table provides a summary of when each of the various tools can be useful to:

  • People seeking unknown close relatives
  • People who already know who their close relatives are, but are seeking additional information or clues about their genealogy

I considered rating these on a 1 to 10 scale, but the relative usefulness of these tools is dependent on many factors, so different tools will be more or less useful to different people.

For example, ethnicity is very useful if someone is admixed from different populations, or even 100% of a specific endogamous population. It’s less useful if the tester is 100% European, regardless of whether they are seeking close relatives or not. Conversely, even “vanilla” ethnicity can be used to rule out majority or recent admixture with many populations.

Tools Unknown Close Relative Seekers Known Close Relatives – Enhance Genealogy
Ethnicity Yes, to identify or rule out populations Yes
Ethnicity Painting Yes, possibly, depending on population Yes, possibly, depending on population
Ethnicity Phasing Yes, possibly, depending on population Yes, possibly, depending on population
DNA Communities Yes, possibly, depending on population Yes, possibly, depending on population
Genetic Groups Possibly, depending on population Possibly, depending on population
Family Matching aka Bucketing Not if parents are entirely unknown, but yes if one parent is known Yes
Chromosome Browser Unlikely Yes
AutoClusters Yes Yes, especially at MyHeritage if Jewish
Estimated Relationships High Not No
Relationship Range High Not reliably No
More, Smaller Segments Unlikely Unlikely other than confirmation
Match List Download Yes Yes
Surnames Yes Yes
Locations Yes Yes
Projects Yes Yes
Y DNA Yes, males only, direct paternal line, identifies surname lineage Yes, males only, direct paternal line, identifies and correctly places surname lineage
Mitochondrial DNA Yes, both sexes, direct matrilineal line only Yes, both sexes, direct matrilineal line only
Public Y Tree Yes for locations Yes for locations
Public Mito Tree Yes for locations Yes for locations
Discover Y DNA Yes, for heritage information Yes, for heritage information
Parents Related – ROH Possibly Less useful

Acknowledgments

A HUGE thank you to several people who contributed images and information in order to provide accurate and expanded information on the topic of endogamy. Many did not want to be mentioned by name, but you know who you are!!!

If you have information to add, please post in the comments.

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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!!!

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Genetic Genealogy at 20 Years: Where Have We Been, Where Are We Going and What’s Important?

Not only have we put 2020 in the rear-view mirror, thankfully, we’re at the 20-year, two-decade milestone. The point at which genetics was first added to the toolbox of genealogists.

It seems both like yesterday and forever ago. And yes, I’ve been here the whole time,  as a spectator, researcher, and active participant.

Let’s put this in perspective. On New Year’s Eve, right at midnight, in 2005, I was able to score kit number 50,000 at Family Tree DNA. I remember this because it seemed like such a bizarre thing to be doing at midnight on New Year’s Eve. But hey, we genealogists are what we are.

I knew that momentous kit number which seemed just HUGE at the time was on the threshold of being sold, because I had inadvertently purchased kit 49,997 a few minutes earlier.

Somehow kit 50,000 seemed like such a huge milestone, a landmark – so I quickly bought kits, 49,998, 49,999, and then…would I get it…YES…kit 50,000. Score!

That meant that in the 5 years FamilyTreeDNA had been in business, they had sold on an average of 10,000 kits per year, or 27 kits a day. Today, that’s a rounding error. Then it was momentous!

In reality, the sales were ramping up quickly, because very few kits were sold in 2000, and roughly 20,000 kits had been sold in 2005 alone. I know this because I purchased kit 28,429 during the holiday sale a year earlier.

Of course, I had no idea who I’d test with that momentous New Year’s Eve Y DNA kit, but I assuredly would find someone. A few months later, I embarked on a road trip to visit an elderly family member with that kit in tow. Thank goodness I did, and they agreed and swabbed on the spot, because they are gone today and with them, the story of the Y line and autosomal DNA of their branch.

In the past two decades, almost an entire generation has slipped away, and with them, an entire genealogical library held in their DNA.

Today, more than 40 million people have tested with the four major DNA testing companies, although we don’t know exactly how many.

Lots of people have had more time to focus on genealogy in 2020, so let’s take a look at what’s important? What’s going on and what matters beyond this month or year?

How has this industry changed in the last two decades, and where it is going?

Reflection

This seems like a good point to reflect a bit.

Professor Dan Bradley reflecting on early genetic research techniques in his lab at the Smurfit Institute of Genetics at Trinity College in Dublin. Photo by Roberta Estes

In the beginning – twenty years ago, there were two companies who stuck their toes in the consumer DNA testing water – Oxford Ancestors and Family Tree DNA. About the same time, Sorenson Genomics and GeneTree were also entering that space, although Sorenson was a nonprofit. Today, of those, only FamilyTreeDNA remains, having adapted with the changing times – adding more products, testing, and sophistication.

Bryan Sykes who founded Oxford Ancestors announced in 2018 that he was retiring to live abroad and subsequently passed away in 2020. The website still exists, but the company has announced that they have ceased sales and the database will remain open until Sept 30, 2021.

James Sorenson died in 2008 and the assets of Sorenson Molecular Genealogy Foundation, including the Sorenson database, were sold to Ancestry in 2012. Eventually, Ancestry removed the public database in 2015.

Ancestry dabbled in Y and mtDNA for a while, too, destroying that database in 2014.

Other companies, too many to remember or mention, have come and gone as well. Some of the various company names have been recycled or purchased, but aren’t the same companies today.

In the DNA space, it was keep up, change, die or be sold. Of course, there was the small matter of being able to sell enough DNA kits to make enough money to stay in business at all. DNA processing equipment and a lab are expensive. Not just the equipment, but also the expertise.

The Next Wave

As time moved forward, new players entered the landscape, comprising the “Big 4” testing companies that constitute the ponds where genealogists fish today.

23andMe was the first to introduce autosomal DNA testing and matching. Their goal and focus was always medical genetics, but they recognized the potential in genealogists before anyone else, and we flocked to purchase tests.

Ancestry settled on autosomal only and relies on the size of their database, a large body of genealogy subscribers, and a widespread “feel-good” marketing campaign to sell DNA kits as the gateway to “discover who you are.”

FamilyTreeDNA did and still does offer all 3 kinds of tests. Over the years, they have enhanced both the Y DNA and mitochondrial product offerings significantly and are still known as “the science company.” They are the only company to offer the full range of Y DNA tests, including their flagship Big Y-700, full sequence mitochondrial testing along with matching for both products. Their autosomal product is called Family Finder.

MyHeritage entered the DNA testing space a few years after the others as the dark horse that few expected to be successful – but they fooled everyone. They have acquired companies and partnered along the way which allowed them to add customers (Promethease) and tools (such as AutoCluster by Genetic Affairs), boosting their number of users. Of course, MyHeritage also offers users a records research subscription service that you can try for free.

In summary:

One of the wonderful things that happened was that some vendors began to accept compatible raw DNA autosomal data transfer files from other vendors. Today, FamilyTreeDNA, MyHeritage, and GEDmatch DO accept transfer files, while Ancestry and 23andMe do not.

The transfers and matching are free, but there are either minimal unlock or subscription plans for advanced features.

There are other testing companies, some with niche markets and others not so reputable. For this article, I’m focusing on the primary DNA testing companies that are useful for genealogy and mainstream companion third-party tools that complement and enhance those services.

The Single Biggest Change

As I look back, the single biggest change is that genetic genealogy evolved from the pariah of genealogy where DNA discussion was banned from the (now defunct) Rootsweb lists and summarily deleted for the first few years after introduction. I know, that’s hard to believe today.

Why, you ask?

Reasons varied from “just because” to “DNA is cheating” and then morphed into “because DNA might do terrible things like, maybe, suggest that a person really wasn’t related to an ancestor in a lineage society.”

Bottom line – fear and misunderstanding. Change is exceedingly difficult for humans, and DNA definitely moved the genealogy cheese.

From that awkward beginning, genetic genealogy organically became a “thing,” a specific application of genealogy. There was paper-trail traditional genealogy and then the genetic aspect. Today, for almost everyone, genealogy is “just another tool” in the genealogist’s toolbox, although it does require focused learning, just like any other tool.

DNA isn’t separate anymore, but is now an integral part of the genealogical whole. Having said that, DNA can’t solve all problems or answer all questions, but neither can traditional paper-trail genealogy. Together, each makes the other stronger and solves mysteries that neither can resolve alone.

Synergy.

I fully believe that we have still only scratched the surface of what’s possible.

Inheritance

As we talk about the various types of DNA testing and tools, here’s a quick graphic to remind you of how the different types of DNA are inherited.

  • Y DNA is inherited paternally for males only and informs us of the direct patrilineal (surname) line.
  • Mitochondrial DNA is inherited by everyone from their mothers and informs us of the mother’s matrilineal (mother’s mother’s mother’s) line.
  • Autosomal DNA can be inherited from potentially any ancestor in random but somewhat predictable amounts through both parents. The further back in time, the less identifiable DNA you’ll inherit from any specific ancestor. I wrote about that, here.

What’s Hot and What’s Not

Where should we be focused today and where is this industry going? What tools and articles popped up in 2020 to help further our genealogy addiction? I already published the most popular articles of 2020, here.

This industry started two decades ago with testing a few Y DNA and mitochondrial DNA markers, and we were utterly thrilled at the time. Both tests have advanced significantly and the prices have dropped like a stone. My first mitochondrial DNA test that tested only 400 locations cost more than $800 – back then.

Y DNA and mitochondrial DNA are still critically important to genetic genealogy. Both play unique roles and provide information that cannot be obtained through autosomal DNA testing. Today, relative to Y DNA and mitochondrial DNA, the biggest challenge, ironically, is educating newer genealogists about their potential who have never heard about anything other than autosomal, often ethnicity, testing.

We have to educate in order to overcome the cacophony of “don’t bother because you don’t get as many matches.”

That’s like saying “don’t use the right size wrench because the last one didn’t fit and it’s a bother to reach into the toolbox.” Not to mention that if everyone tested, there would be a lot more matches, but I digress.

If you don’t use the right tool, and all of the tools at your disposal, you’re not going to get the best result possible.

The genealogical proof standard, the gold standard for genealogy research, calls for “a reasonably exhaustive search,” and if you haven’t at least considered if or how Y
DNA
and mitochondrial DNA along with autosomal testing can or might help, then your search is not yet exhaustive.

I attempt to obtain the Y and mitochondrial DNA of every ancestral line. In the article, Search Techniques for Y and Mitochondrial DNA Test Candidates, I described several methodologies to find appropriate testing candidates.

Y DNA – 20 Years and Still Critically Important

Y DNA tracks the Y chromosome for males via the patrilineal (surname) line, providing matching and historical migration information.

We started 20 years ago testing 10 STR markers. Today, we begin at 37 markers, can upgrade to 67 or 111, but the preferred test is the Big Y which provides results for 700+ STR markers plus results from the entire gold standard region of the Y chromosome in order to provide the most refined results. This allows genealogists to use STR markers and SNP results together for various aspects of genealogy.

I created a Y DNA resource page, here, in order to provide a repository for Y DNA information and updates in one place. I would encourage anyone who can to order or upgrade to the Big Y-700 test which provides critical lineage information in addition to and beyond traditional STR testing. Additionally, the Big Y-700 test helps build the Y DNA haplotree which is growing by leaps and bounds.

More new SNPs are found and named EVERY SINGLE DAY today at FamilyTreeDNA than were named in the first several years combined. The 2006 SNP tree listed a grand total of 459 SNPs that defined the Y DNA tree at that time, according to the ISOGG Y DNA SNP tree. Goran Rundfeldt, head of R&D at FamilyTreeDNA posted this today:

2020 was an awful year in so many ways, but it was an unprecedented year for human paternal phylogenetic tree reconstruction. The FTDNA Haplotree or Great Tree of Mankind now includes:

37,534 branches with 12,696 added since 2019 – 51% growth!
defined by
349,097 SNPs with 131,820 added since 2019 – 61% growth!

In just one year, 207,536 SNPs were discovered and assigned FT SNP names. These SNPs will help define new branches and refine existing ones in the future.

The tree is constructed based on high coverage chromosome Y sequences from:
– More than 52,500 Big Y results
– Almost 4,000 NGS results from present-day anonymous men that participated in academic studies

Plus an additional 3,000 ancient DNA results from archaeological remains, of mixed quality and Y chromosome coverage at FamilyTreeDNA.

Wow, just wow.

These three new articles in 2020 will get you started on your Y DNA journey!

Mitochondrial DNA – Matrilineal Line of Humankind is Being Rewritten

The original Oxford Ancestor’s mitochondrial DNA test tested 400 locations. The original Family Tree DNA test tested around 1000 locations. Today, the full sequence mitochondrial DNA test is standard, testing the entire 16,569 locations of the mitochondria.

Mitochondrial DNA tracks your mother’s direct maternal, or matrilineal line. I’ve created a mitochondrial DNA resource page, here that includes easy step-by-step instructions for after you receive your results.

New articles in 2020 included the introduction of The Million Mito Project. 2021 should see the first results – including a paper currently in the works.

The Million Mito Project is rewriting the haplotree of womankind. The current haplotree has expanded substantially since the first handful of haplogroups thanks to thousands upon thousands of testers, but there is so much more information that can be extracted today.

Y and Mitochondrial Resources

If you don’t know of someone in your family to test for Y DNA or mitochondrial DNA for a specific ancestral line, you can always turn to the Y DNA projects at Family Tree DNA by searching here.

The search provides you with a list of projects available for a specific surname along with how many customers with that surname have tested. Looking at the individual Y DNA projects will show the earliest known ancestor of the surname line.

Another resource, WikiTree lists people who have tested for the Y DNA, mitochondrial DNA and autosomal DNA lines of specific ancestors.

Click on images to enlarge

On the left side, my maternal great-grandmother’s profile card, and on the right, my paternal great-great-grandfather. You can see that someone has tested for the mitochondrial DNA of Nora (OK, so it’s me) and the Y DNA of John Estes (definitely not me.)

MitoYDNA, a nonprofit volunteer organization created a comparison tool to replace Ysearch and Mitosearch when they bit the dust thanks to GDPR.

MitoYDNA accepts uploads from different sources and allows uploaders to not only match to each other, but to view the STR values for Y DNA and the mutation locations for the HVR1 and HVR2 regions of mitochondrial DNA. Mags Gaulden, one of the founders, explains in her article, What sets mitoYDNA apart from other DNA Databases?.

If you’ve tested at nonstandard companies, not realizing that they didn’t provide matching, or if you’ve tested at a company like Sorenson, Ancestry, and now Oxford Ancestors that is going out of business, uploading your results to mitoYDNA is a way to preserve your investment. PS – I still recommend testing at FamilyTreeDNA in order to receive detailed results and compare in their large database.

CentiMorgans – The Word of Two Decades

The world of autosomal DNA turns on the centimorgan (cM) measure. What is a centimorgan, exactly? I wrote about that unit of measure in the article Concepts – CentiMorgans, SNPs and Pickin’ Crab.

Fortunately, new tools and techniques make using cMs much easier. The Shared cM Project was updated this year, and the results incorporated into a wonderfully easy tool used to determine potential relationships at DNAPainter based on the number of shared centiMorgans.

Match quality and potential relationships are determined by the number of shared cMs, and the chromosome browser is the best tool to use for those comparisons.

Chromosome Browser – Genetics Tool to View Chromosome Matches

Chromosome browsers allow testers to view their matching cMs of DNA with other testers positioned on their own chromosomes.

My two cousins’ DNA where they match me on chromosomes 1-4, is shown above in blue and red at Family Tree DNA. It’s important to know where you match cousins, because if you match multiple cousins on the same segment, from the same side of your family (maternal or paternal), that’s suggestive of a common ancestor, with a few caveats.

Some people feel that a chromosome browser is an advanced tool, but I think it’s simply standard fare – kind of like driving a car. You need to learn how to drive initially, but after that, you don’t even think about it – you just get in and go. Here’s help learning how to drive that chromosome browser.

Triangulation – Science Plus Group DNA Matching Confirms Genealogy

The next logical step after learning to use a chromosome browser is triangulation. If fact, you’re seeing triangulation above, but don’t even realize it.

The purpose of genetic genealogy is to gather evidence to “prove” ancestral connections to either people or specific ancestors. In autosomal DNA, triangulation occurs when:

  • You match at least two other people (not close relatives)
  • On the same reasonably sized segment of DNA (generally 7 cM or greater)
  • And you can assign that segment to a common ancestor

The same two cousins are shown above, with triangulated segments bracketed at MyHeritage. I’ve identified the common ancestor with those cousins that those matching DNA segments descend from.

MyHeritage’s triangulation tool confirms by bracketing that these cousins also match each other on the same segment, which is the definition of triangulation.

I’ve written a lot about triangulation recently.

If you’d prefer a video, I recorded a “Top Tips” Facebook LIVE with MyHeritage.

Why is Ancestry missing from this list of triangulation articles? Ancestry does not offer a chromosome browser or segment information. Therefore, you can’t triangulate at Ancestry. You can, however, transfer your Ancestry DNA raw data file to either FamilyTreeDNA, MyHeritage, or GEDmatch, all three of which offer triangulation.

Step by step download/upload transfer instructions are found in this article:

Clustering Matches and Correlating Trees

Based on what we’ve seen over the past few years, we can no longer depend on the major vendors to provide all of the tools that genealogists want and need.

Of course, I would encourage you to stay with mainstream products being used by a significant number of community power users. As with anything, there is always someone out there that’s less than honorable.

2020 saw a lot of innovation and new tools introduced. Maybe that’s one good thing resulting from people being cooped up at home.

Third-party tools are making a huge difference in the world of genetic genealogy. My favorites are Genetic Affairs, their AutoCluster tool shown above, DNAPainter and DNAGedcom.

These articles should get you started with clustering.

If you like video resources, here’s a MyHeritage Facebook LIVE that I recorded about how to use AutoClusters:

I created a compiled resource article for your convenience, here:

I have not tried a newer tool, YourDNAFamily, that focuses only on 23andMe results although the creator has been a member of the genetic genealogy community for a long time.

Painting DNA Makes Chromosome Browsers and Triangulation Easy

DNAPainter takes the next step, providing a repository for all of your painted segments. In other words, DNAPainter is both a solution and a methodology for mass triangulation across all of your chromosomes.

Here’s a small group of people who match me on the same maternal segment of chromosome 1, including those two cousins in the chromosome browser and triangulation sections, above. We know that this segment descends from Philip Jacob Miller and his wife because we’ve been able to identify that couple as the most distant ancestor intersection in all of our trees.

It’s very helpful that DNAPainter has added the functionality of painting all of the maternal and paternal bucketed matches from Family Tree DNA.

All you need to do is to link your known matches to your tree in the proper place at FamilyTreeDNA, then they do the rest by using those DNA matches to indicate which of the rest of your matches are maternal and paternal. Instructions, here. You can then export the file and use it at DNAPainter to paint all of those matches on the correct maternal or paternal chromosomes.

Here’s an article providing all of the DNAPainter Instructions and Resources.

DNA Matches Plus Trees Enhance Genealogy

Of course, utilizing DNA matching plus finding common ancestors in trees is one of the primary purposes of genetic genealogy – right?

Vendors have linked the steps of matching DNA with matching ancestors in trees.

Genetic Affairs take this a step further. If you don’t have an ancestor in your tree, but your matches have common ancestors with each other, Genetic Affairs assembles those trees to provide you with those hints. Of course, that common ancestor might not be relevant to your genealogy, but it just might be too!

click to enlarge

This tree does not include me, but two of my matches descend from a common ancestor and that common ancestor between them might be a clue as to why I match both of them.

Ethnicity Continues to be Popular – But Is No Shortcut to Genealogy

Ethnicity is always popular. People want to “do their DNA” and find out where they come from. I understand. I really do. Who doesn’t just want an answer?

Of course, it’s not that simple, but that doesn’t mean it’s not disappointing to people who test for that purpose with high expectations. Hopefully, ethnicity will pique their curiosity and encourage engagement.

All four major vendors rolled out updated ethnicity results or related tools in 2020.

The future for ethnicity, I believe, will be held in integrated tools that allow us to use ethnicity results for genealogy, including being able to paint our ethnicity on our chromosomes as well as perform segment matching by ethnicity.

For example, if I carry an African segment on chromosome 1 from my father, and I match one person from my mother’s side and one from my father’s side on that same segment – one or the other of those people should also have that segment identified as African. That information would inform me as to which match is paternal and which is maternal

Not only that, this feature would help immensely tracking ancestors back in time and identifying their origins.

Will we ever get there? I don’t know. I’m not sure ethnicity is or can be accurate enough. We’ll see.

Transition to Digital and Online

Sometimes the future drags us kicking and screaming from the present.

With the imposed isolation of 2020, conferences quickly moved to an online presence. The genealogy community has all pulled together to make this work. The joke is that 2020’s most used phrase is “can you hear me?” I can vouch for that.

Of course while the year 2020 is over, the problem isn’t and is extending at least through the first half of 2021 and possibly longer. Conferences are planned months, up to a year, in advance and they can’t turn on a dime, so don’t even begin to expect in-person conferences until either late in 2021 or more likely, 2022 if all goes well this year.

I expect the future will eventually return to in-person conferences, but not entirely.

Finding ways to be more inclusive allows people who don’t want to or can’t travel or join in-person to participate.

I’ve recorded several sessions this year, mostly for 2021. Trust me, these could be a comedy, mostly of errors😊

I participated in four MyHeritage Facebook LIVE sessions in 2020 along with some other amazing speakers. This is what “live” events look like today!

Screenshot courtesy MyHeritage

A few days ago, I asked MyHeritage for a list of their LIVE sessions in 2020 and was shocked to learn that there were more than 90 in English, all free, and you can watch them anytime. Here’s the MyHeritage list.

By the way, every single one of the speakers is a volunteer, so say a big thank you to the speakers who make this possible, and to MyHeritage for the resources to make this free for everyone. If you’ve ever tried to coordinate anything like this, it’s anything but easy.

Additonally, I’ve created two Webinars this year for Legacy Family Tree Webinars.

Geoff Rasmussen put together the list of their top webinars for 2020, and I was pleased to see that I made the top 10! I’m sure there are MANY MORE you’d be interested in watching. Personally, I’m going to watch #6 yet today! Also, #9 and #22. You can always watch new webinars for free for a few days, and you can subscribe to watch all webinars, here.

The 2021 list of webinar speakers has been announced here, and while I’m not allowed to talk about something really fun that’s upcoming, let’s just say you definitely have something to look forward to in the springtime!

Also, don’t forget to register for RootsTech Connect which is entirely online and completely free, February 25-27, here.

Thank you to Penny Walters for creating this lovely graphic.

There are literally hundreds of speakers providing sessions in many languages for viewers around the world. I’ve heard the stats, but we can’t share them yet. Let me just say that you will be SHOCKED at the magnitude and reach of this conference. I’m talking dumbstruck!

During one of our zoom calls, one of the organizers says it feels like we’re constructing the plane as we’re flying, and I can confirm his observation – but we are getting it done – together! All hands on deck.

I’ll be presenting an advanced session about triangulation as well as a mini-session in the FamilySearch DNA Resource Center about finding your mother’s ancestors. I’ll share more information as it’s released and I can.

Companies and Owners Come & Go

You probably didn’t even notice some of these 2020 changes. Aside from the death of Bryan Sykes (RIP Bryan,) the big news and the even bigger unknown is the acquisition of Ancestry by Blackstone. Recently the CEO, Margo Georgiadis announced that she was stepping down. The Ancestry Board of Directors has announced an external search for a new CEO. All I can say is that very high on the priority list should be someone who IS a genealogist and who understands how DNA applies to genealogy.

Other changes included:

In the future, as genealogy and DNA testing becomes ever more popular and even more of a commodity, company sales and acquisitions will become more commonplace.

Some Companies Reduced Services and Cut Staff

I understand this too, but it’s painful. The layoffs occurred before Covid, so they didn’t result from Covid-related sales reductions. Let’s hope we see renewed investment after the Covid mess is over.

In a move that may or may not be related to an attempt to cut costs, Ancestry removed 6 and 7 cM matches from their users, freeing up processing resources, hardware, and storage requirements and thereby reducing costs.

I’m not going to beat this dead horse, because Ancestry is clearly not going to move on this issue, nor on that of the much-requested chromosome browser.

Later in the year, 23andMe also removed matches and other features, although, to their credit, they have restored at least part of this functionality and have provided ethnicity updates to V3 and V4 kits which wasn’t initially planned.

It’s also worth noting that early in 2020, 23andMe laid off 100 people as sales declined. Since that time, 23andMe has increasingly pushed consumers to pay to retest on their V5 chip.

About the same time, Ancestry also cut their workforce by about 6%, or about 100 people, also citing a slowdown in the consumer testing market. Ancestry also added a health product.

I’m not sure if we’ve reached market saturation or are simply seeing a leveling off. I wrote about that in DNA Testing Sales Decline: Reason and Reasons.

Of course, the pandemic economy where many people are either unemployed or insecure about their future isn’t helping.

The various companies need some product diversity to survive downturns. 23andMe is focused on medical research with partners who pay 23andMe for the DNA data of customers who opt-in, as does Ancestry.

Both Ancestry and MyHeritage provide subscription services for genealogy records.

FamilyTreeDNA is part of a larger company, GenebyGene whose genetics labs do processing for other companies and medical facilities.

A huge thank you to both MyHeritage and FamilyTreeDNA for NOT reducing services to customers in 2020.

Scientific Research Still Critical & Pushes Frontiers

Now that DNA testing has become a commodity, it’s easy to lose track of the fact that DNA testing is still a scientific endeavor that requires research to continue to move forward.

I’m still passionate about research after 20 years – maybe even more so now because there’s so much promise.

Research bleeds over into the consumer marketplace where products are improved and new features created allowing us to better track and understand our ancestors through their DNA that we and our family members inherit.

Here are a few of the research articles I published in 2020. You might notice a theme here – ancient DNA. What we can learn now due to new processing techniques is absolutely amazing. Labs can share files and information, providing the ability to “reprocess” the data, not the DNA itself, as more information and expertise becomes available.

Of course, in addition to this research, the Million Mito Project team is hard at work rewriting the tree of womankind.

If you’d like to participate, all you need to do is to either purchase a full sequence mitochondrial DNA kit at FamilyTreeDNA, or upgrade to the full sequence if you tested at a lower level previously.

Predictions

Predictions are risky business, but let me give it a shot.

Looking back a year, Covid wasn’t on the radar.

Looking back 5 years, neither Genetic Affairs nor DNAPainter were yet on the scene. DNAAdoption had just been formed in 2014 and DNAGedcom which was born out of DNAAdoption didn’t yet exist.

In other words, the most popular tools today didn’t exist yet.

GEDmatch, founded in 2010 by genealogists for genealogists was 5 years old, but was sold in December 2019 to Verogen.

We were begging Ancestry for a chromosome browser, and while we’ve pretty much given up beating them, because the horse is dead and they can sell DNA kits through ads focused elsewhere, that doesn’t mean genealogists still don’t need/want chromosome and segment based tools. Why, you’d think that Ancestry really doesn’t want us to break through those brick walls. That would be very bizarre, because every brick wall that falls reveals two more ancestors that need to be researched and spurs a frantic flurry of midnight searching. If you’re laughing right now, you know exactly what I mean!

Of course, if Ancestry provided a chromosome browser, it would cost development money for no additional revenue and their customer service reps would have to be able to support it. So from Ancestry’s perspective, there’s no good reason to provide us with that tool when they can sell kits without it. (Sigh.)

I’m not surprised by the management shift at Ancestry, and I wouldn’t be surprised to see several big players go public in the next decade, if not the next five years.

As companies increase in value, the number of private individuals who could afford to purchase the company decreases quickly, leaving private corporations as the only potential buyers, or becoming publicly held. Sometimes, that’s a good thing because investment dollars are infused into new product development.

What we desperately need, and I predict will happen one way or another is a marriage of individual tools and functions that exist separately today, with a dash of innovation. We need tools that will move beyond confirming existing ancestors – and will be able to identify ancestors through our DNA – out beyond each and every brick wall.

If a tester’s DNA matches to multiple people in a group descended from a particular previously unknown couple, and the timing and geography fits as well, that provides genealogical researchers with the hint they need to begin excavating the traditional records, looking for a connection.

In fact, this is exactly what happened with mitochondrial DNA – twice now. A match and a great deal of digging by one extremely persistent cousin resulting in identifying potential parents for a brick-wall ancestor. Autosomal DNA then confirmed that my DNA matched with 59 other individuals who descend from that couple through multiple children.

BUT, we couldn’t confirm those ancestors using autosomal DNA UNTIL WE HAD THE NAMES of the couple. DNA has the potential to reveal those names!

I wrote about that in Mitochondrial DNA Bulldozes Brick Wall and will be discussing it further in my RootsTech presentation.

The Challenge

We have most of the individual technology pieces today to get this done. Of course, the combined technological solution would require significant computing resources and processing power – just at the same time that vendors are desperately trying to pare costs to a minimum.

Some vendors simply aren’t interested, as I’ve already noted.

However, the winner, other than us genealogists, of course, will be the vendor who can either devise solutions or partner with others to create the right mix of tools that will combine matching, triangulation, and trees of your matches to each other, even if you don’t’ share a common ancestor.

We need to follow the DNA past the current end of the branch of our tree.

Each triangulated segment has an individual history that will lead not just to known ancestors, but to their unknown ancestors as well. We have reached critical mass in terms of how many people have tested – and more success would encourage more and more people to test.

There is a genetic path over every single brick wall in our genealogy.

Yes, I know that’s a bold statement. It’s not future Jetson’s flying-cars stuff. It’s doable – but it’s a matter of commitment, investment money, and finding a way to recoup that investment.

I don’t think it’s possible for the one-time purchase of a $39-$99 DNA test, especially when it’s not a loss-leader for something else like a records or data subscription (MyHeritage and Ancestry) or a medical research partnership (Ancestry and 23andMe.)

We’re performing these analysis processes manually and piecemeal today. It’s extremely inefficient and labor-intensive – which is why it often fails. People give up. And the process is painful, even when it does succeed.

This process has also been made increasingly difficult when some vendors block tools that help genealogists by downloading match and ancestral tree information. Before Ancestry closed access, I was creating theories based on common ancestors in my matches trees that weren’t in mine – then testing those theories both genetically (clusters, AutoTrees and ThruLines) and also by digging into traditional records to search for the genetic connection.

For example, I’m desperate to identify the parents of my James Lee Clarkson/Claxton, so I sorted my spreadsheet by surname and began evaluating everyone who had a Clarkson/Claxton in their tree in the 1700s in Virginia or North Carolina. But I can’t do that anymore now, either with a third-party tool or directly at Ancestry. Twenty million DNA kits sold for a minimum of $79 equals more than 1.5 billion dollars. Obviously, the issue here is not a lack of funds.

Including Y and mitochondrial DNA resources in our genetic toolbox not only confirms accuracy but also provides additional hints and clues.

Sometimes we start with Y DNA or mitochondrial DNA, and wind up using autosomal and sometimes the reverse. These are not competing products. It’s not either/or – it’s *and*.

Personally, I don’t expect the vendors to provide this game-changing complex functionality for free. I would be glad to pay for a subscription for top-of-the-line innovation and tools. In what other industry do consumers expect to pay for an item once and receive constant life-long innovations and upgrades? That doesn’t happen with software, phones nor with automobiles. I want vendors to be profitable so that they can invest in new tools that leverage the power of computing for genealogists to solve currently unsolvable problems.

Every single end-of-line ancestor in your tree represents a brick wall you need to overcome.

If you compare the cost of books, library visits, courthouse trips, and other research endeavors that often produce exactly nothing, these types of genetic tools would be both a godsend and an incredible value.

That’s it.

That’s the challenge, a gauntlet of sorts.

Who’s going to pick it up?

I can’t answer that question, but I can say that 23andMe can’t do this without supporting extensive trees, and Ancestry has shown absolutely no inclination to support segment data. You can’t achieve this goal without segment information or without trees.

Among the current players, that leaves two DNA testing companies and a few top-notch third parties as candidates – although – as the past has proven, the future is uncertain, fluid, and everchanging.

It will be interesting to see what I’m writing at the end of 2025, or maybe even at the end of 2021.

Stay tuned.

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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

Books

Y DNA Resources and Repository

I’ve created a Y DNA resource page with the information in this article, here, as a permanent location where you can find Y DNA information in one place – including:

  • Step-by-step guides about how to utilize Y DNA for your genealogy
  • Educational articles and links to the latest webinars
  • Articles about the science behind Y DNA
  • Ancient DNA
  • Success stories

Please feel free to share this resource or any of the links to individual articles with friends, genealogy groups, or on social media.

If you haven’t already taken a Y DNA test, and you’re a male (only males have a Y chromosome,) you can order one here. If you also purchase the Family Finder, autosomal test, those results can be used to search together.

What is Y DNA?

Y DNA is passed directly from fathers to their sons, as illustrated by the blue arrow, above. Daughters do not inherit the Y chromosome. The Y chromosome is what makes males, male.

Every son receives a Y chromosome from his father, who received it from his father, and so forth, on up the direct patrilineal line.

Comparatively, mitochondrial DNA, the pink arrow, is received by both sexes of children from the mother through the direct matrilineal line.

Autosomal DNA, the green arrow, is a combination of randomly inherited DNA from many ancestors that is inherited by both sexes of children from both parents. This article explains a bit more.

Y DNA has Unique Properties

The Y chromosome is never admixed with DNA from the mother, so the Y chromosome that the son receives is identical to the father’s Y chromosome except for occasional minor mutations that take place every few generations.

This lack of mixture with the mother’s DNA plus the occasional mutation is what makes the Y chromosome similar enough to match against other men from the same ancestors for hundreds or thousands of years back in time, and different enough to be useful for genealogy. The mutations can be tracked within extended families.

In western cultures, the Y chromosome path of inheritance is usually the same as the surname, which means that the Y chromosome is uniquely positioned to identify the direct biological patrilineal lineage of males.

Two different types of Y DNA tests can be ordered that work together to refine Y DNA results and connect testers to other men with common ancestors.

FamilyTreeDNA provides STR tests with their 37, 67 and 111 marker test panels, and comprehensive STR plus SNP testing with their Big Y-700 test.

click to enlarge

STR markers are used for genealogy matching, while SNP markers work with STR markers to refine genealogy further, plus provide a detailed haplogroup.

Think of a haplogroup as a genetic clan that tells you which genetic family group you belong to – both today and historically, before the advent of surnames.

This article, What is a Haplogroup? explains the basic concept of how haplogroups are determined.

In addition to the Y DNA test itself, Family Tree DNA provides matching to other testers in their database plus a group of comprehensive tools, shown on the dashboard above, to help testers utilize their results to their fullest potential.

You can order or upgrade a Y DNA test, here. If you also purchase the Family Finder, autosomal test, those results can be used to search together.

Step-by-Step – Using Your Y DNA Results

Let’s take a look at all of the features, functions, and tools that are available on your FamilyTreeDNA personal page.

What do those words mean? Here you go!

Come along while I step through evaluating Big Y test results.

Big Y Testing and Results

Why would you want to take a Big Y test and how can it help you?

While the Big Y-500 has been superseded by the Big Y-700 test today, you will still be interested in some of the underlying technology. STR matching still works the same way.

The Big Y-500 provided more than 500 STR markers and the Big Y-700 provides more than 700 – both significantly more than the 111 panel. The only way to receive these additional markers is by purchasing the Big Y test.

I have to tell you – I was skeptical when the Big Y-700 was introduced as the next step above the Big Y-500. I almost didn’t upgrade any kits – but I’m so very glad that I did. I’m not skeptical anymore.

This Y DNA tree rocks. A new visual format with your matches listed on their branches. Take a look!

Educational Articles

I’ve been writing about DNA for years and have selected several articles that you may find useful.

What kinds of information are available if you take a Y DNA test, and how can you use it for genealogy?

What if your father isn’t available to take a DNA test? How can you determine who else to test that will reveal your father’s Y DNA information?

Family Tree DNA shows the difference in the number of mutations between two men as “genetic distance.” Learn what that means and how it’s figured in this article.

Of course, there were changes right after I published the original Genetic Distance article. The only guarantees in life are death, taxes, and that something will change immediately after you publish.

Sometimes when we take DNA tests, or others do, we discover the unexpected. That’s always a possibility. Here’s the story of my brother who wasn’t my biological brother. If you’d like to read more about Dave’s story, type “Dear Dave” into the search box on my blog. Read the articles in publication order, and not without a box of Kleenex.

Often, what surprise matches mean is that you need to dig further.

The words paternal and patrilineal aren’t the same thing. Paternal refers to the paternal half of your family, where patrilineal is the direct father to father line.

Just because you don’t have any surname matches doesn’t necessarily mean it’s because of what you’re thinking.

Short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs) aren’t the same thing and are used differently in genealogy.

Piecing together your ancestor’s Y DNA from descendants.

Haplogroups are something like our pedigree charts.

What does it mean when you have a zero for a marker value?

There’s more than one way to break down that brick wall. Here’s how I figured out which of 4 sons was my ancestor.

Just because you match the right line autosomally doesn’t mean it’s because you descend from the male child you think is your ancestor. Females gave their surnames to children born outside of a legal marriage which can lead to massive confusion. This is absolutely why you need to test the Y DNA of every single ancestral line.

When the direct patrilineal line isn’t the line you’re expecting.

You can now tell by looking at the flags on the haplotree where other people’s ancestral lines on your branch are from. This is especially useful if you’ve taken the Big Y test and can tell you if you’re hunting in the right location.

If you’re just now testing or tested in 2018 or after, you don’t need to read this article unless you’re interested in the improvements to the Big Y test over the years.

2019 was a banner year for discovery. 2020 was even more so, keeping up an amazing pace. I need to write a 2020 update article.

What is a terminal SNP? Hint – it’s not fatal😊

How the TIP calculator works and how to best interpret the results. Note that this tool is due for an update that incorporates more markers and SNP results too.

You can view the location of the Y DNA and mitochondrial DNA ancestors of people whose ethnicity you match.

Tools and Techniques

This free public tree is amazing, showing locations of each haplogroup and totals by haplogroup and country, including downstream branches.

Need to search for and find Y DNA candidates when you don’t know anyone from that line? Here’s how.

Yes, it’s still possible to resolve this issue using autosomal DNA. Non-matching Y DNA isn’t the end of the road, just a fork.

Science Meets Genealogy – Including Ancient DNA

Haplogroup C was an unexpected find in the Americas and reaches into South America.

Haplogroup C is found in several North American tribes.

Haplogroup C is found as far east as Nova Scotia.

Test by test, we made progress.

New testers, new branches. The research continues.

The discovery of haplogroup A00 was truly amazing when it occurred – the base of the phylotree in Africa.

The press release about the discovery of haplogroup A00.

In 2018, a living branch of A00 was discovered in Africa, and in 2020, an ancient DNA branch.

Did you know that haplogroups weren’t always known by their SNP names?

This brought the total of SNPs discovered by Family Tree DNA in mid-2018 to 153,000. I should contact the Research Center to see how many they have named at the end of 2020.

An academic paper split ancient haplogroup D, but then the phylogenetic research team at FamilyTreeDNA split it twice more! This might not sound exciting until you realize this redefines what we know about early man, in Africa and as he emerged from Africa.

Ancient DNA splits haplogroup P after analyzing the remains of two Jehai people from West Malaysia.

For years I doubted Kennewick Man’s DNA would ever be sequenced, but it finally was. Kennewick Man’s mitochondrial DNA haplogroup is X2a and his Y DNA was confirmed to Q-M3 in 2015.

Compare your own DNA to Vikings!

Twenty-seven Icelandic Viking skeletons tell a very interesting story.

Irish ancestors? Check your DNA and see if you match.

Ancestors from Hungary or Italy? Take a look. These remains have matches to people in various places throughout Europe.

The Y DNA story is no place near finished. Dr. Miguel Vilar, former Lead Scientist for National Geographic’s Genographic Project provides additional analysis and adds a theory.

Webinars

Y DNA Webinar at Legacy Family Tree Webinars – a 90-minute webinar for those who prefer watching to learn! It’s not free, but you can subscribe here.

Success Stories and Genealogy Discoveries

Almost everyone has their own Y DNA story of discovery. Because the Y DNA follows the surname line, Y DNA testing often helps push those lines back a generation, or two, or four. When STR markers fail to be enough, we can turn to the Big Y-700 test which provides SNP markers down to the very tip of the leaves in the Y DNA tree. Often, but not always, family-defining SNP branches will occur which are much more stable and reliable than STR mutations – although SNPs and STRs should be used together.

Methodologies to find ancestral lines to test, or maybe descendants who have already tested.

DNA testing reveals an unexpected mystery several hundred years old.

When I write each of my “52 Ancestor” stories, I include genetic information, for the ancestor and their descendants, when I can. Jacob was special because, in addition to being able to identify his autosomal DNA, his Y DNA matches the ancient DNA of the Yamnaya people. You can read about his Y DNA story in Jakob Lenz (1748-1821), Vinedresser.

Please feel free to add your success stories in the comments.

What About You?

You never know what you’re going to discover when you test your Y DNA. If you’re a female, you’ll need to find a male that descends from the line you want to test via all males to take the Y DNA test on your behalf. Of course, if you want to test your father’s line, your father, or a brother through that father, or your uncle, your father’s brother, would be good candidates.

What will you be able to discover? Who will the earliest known ancestor with that same surname be among your matches? Will you be able to break down a long-standing brick wall? You’ll never know if you don’t test.

You can click here to upgrade an existing test or order a Y DNA test.

Share the Love

You can always forward these articles to friends or share by posting links on social media. Who do you know that might be interested?

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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

Books

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

Glossary – DNA – Deoxyribonucleic Acid

What is DNA and why do I care?

Good questions. Let’s take a look at the answer in general, then why we use DNA for genealogy.

The Recipe for You

DNA, deoxyribonucleic acid, is the book of life for all organisms. In essence, it’s the recipe for you – and what makes you unique.

DNA is formed of strands that twist to form the familiar double helix pattern.

The two strands are joined together by one of 4 different nucleotides, one extending from each side to connect in the middle. The nucleotides are:

  • Cytosine – C
  • Guanine – G
  • Thymine – T
  • Adenine – A

The nucleotide names don’t really matter for genetic genealogy, but what does matter is that the sequence of these nucleotides when chained together is what encodes information on long structures called chromosomes. Each person carries 22 chromosomes, plus the 23rd chromosome pair which is gender specific.

Using DNA for Genetic Genealogy

There are four different kinds of DNA that genealogists use in different ways for obtaining ancestors’ information relevant to genetic genealogy. Thankfully, we have 4 different kinds of DNA available to us because of unique inheritance patterns for each kind of DNA – meaning we inherited different kinds of DNA from different ancestral paths. If one kind of DNA doesn’t work in a particular situation, chances are good that another type will.

Genetic genealogy makes use of 4 different types of DNA.

  • Y DNA – passed from males to male children, only (your father’s paternal line)
  • Mitochondrial DNA – passed from females to both genders of children, but only females pass it on (your mother’s matrilineal line)

Y and mitochondrial DNA inheritance paths are shown on a pedigree chart in the graphic below, with the blue boxes representing Y DNA and the red circles representing mitochondrial DNA inheritance.

In addition to Y and mitochondrial DNA, genetic genealogists also use two kinds of DNA that reflect inheritance from additional ancestral lines, in addition to the red and blue lines shown above – meaning the ancestral lines with no color.

  • Autosomal DNA – the 22 chromosomes that recombine during reproduction.
  • X Chromosome – always contributed by the mother, but only contributed by the father to female children – this is the 23rd chromosome pair which recombines with a unique inheritance pattern.  You can read more about that in the article, X Marks the Spot.

Receiving What Kind of DNA from Whom

While the Y and mitochondrial DNA have unique and very prescribed inheritance patterns as shown by the red arrows pointing to the blue Y chromosome below at far left, and the red mitochondrial circles at far right, the 22 autosomal chromosomes are contributed equally by each parent. In other words, for each chromosome, a child inherits half of each parent’s DNA. How the selection of which DNA is contributed to each child is unknown.

A child’s gender is determined by the parent’s contributions to the 23rd chromosome, not shown above. The following chart explains gender determination by the X and Y combinations of the 23rd chromosome.

Received from Mother Received from Father
Male child X Y
Female child X X

The Y chromosome is what makes males male.

No Y chromosome?  You’re a female.

However, this X chromosome inheritance pattern provides us with the ability to look at X matches for males and know immediately that they had to have come from his mother’s lineage – because males don’t inherit an X chromosome from their father.

Autosomal DNA and Genetic Genealogy

The 22 non-gender chromosomes recombine in each generation, with half of each chromosome being contributed by each parent, as shown in the illustrations above.

You can see that in the first generation, the child received one blue and one yellow, or one pink and one green, chromosome. In giving each child exactly half of their DNA, each parent contributes some amount of ancestral DNA from generations upstream, as you can see in the mother/father and son/daughter generations.

For example, each child receives, on average, 25% of each of their grandparent’s DNA – although they can receive somewhat more or less than 25%, depending on the random nature of recombination.

Therefore, genetic genealogy testing companies compare tester’s autosomal DNA with other testers and look for common segments contributed by common ancestors, resulting in autosomal matching.

When relatively large segments match between three or more relatives who are not immediate family, we can attribute that DNA to a common ancestor. Of course, the challenge, and the thrill, is to determine which common ancestor contributed that common DNA to our triangulated match group. It’s a great way to verify our research and to break down brick walls.

Let’s face it, you received ALL of your DNA from SOME combination of ancestors, and if you carry large enough pieces from any specific ancestor, we can, hopefully, identify the source of that DNA segment by looking at the genealogy of those we match on that segment.

It’s a great puzzle to unravel, and best of all, it’s the puzzle of you.

More Info

The great news is that you can utilize your Y DNA, mitochondrial DNA and autosomal DNA differently, to provide you with different kinds of information about different ancestors and genealogy lines.

If you’d like to read more about how the 4 Kinds of DNA can be used, please read the short article, 4 Kinds of DNA for Genetic Genealogy.

You can also enter any word or phrase into the search box in the upper right hand corner of this blog to find additional useful information about any topic.

If You Want to Test

If you’d like to learn more about the various kinds of DNA tests available, and which one or ones would be the best for you, please read the article, Which DNA Test is Best?

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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