The Best of 2022

It’s that time of year where we look both backward and forward.

Thank you for your continued readership! Another year under our belts!

I always find it interesting to review the articles you found most interesting this past year.

In total, I published 97 articles in 2022, of which 56 were directly instructional about genetic genealogy. I say “directly instructional,” because, as you know, the 52 Ancestors series of articles are instructional too, but told through the lives of my ancestors. That leaves 41 articles that were either 52 Ancestors articles, or general in nature.

It has been quite a year.

2022 Highlights

In a way, writing these articles serves as a journal for the genetic genealogy community. I never realized that until I began scanning titles a year at a time.

Highlights of 2022 include:

Which articles were your favorites that were published in 2022, and why?

Your Favorites

Often, the topics I select for articles are directly related to your comments, questions and suggestions, especially if I haven’t covered the topic previously, or it needs to be featured again. Things change in this industry, often. That’s a good thing!

However, some articles become forever favorites. Current articles don’t have enough time to amass the number of views accumulated over years for articles published earlier, so recently published articles are often NOT found in the all-time favorites list.

Based on views, what are my readers’ favorites and what do they find most useful?

In the chart below, the 2022 ranking is not just the ranking of articles published in 2022, but the ranking of all articles based on 2022 views alone. Not surprisingly, six of the 15 favorite 2022 articles were published in 2022.

The All-Time Ranking is the ranking for those 2022 favorites IF they fell within the top 15 in the forever ranking, over the entire decade+ that this blog has existed.

Drum roll please!!!

Article Title Publication Date 2022 Ranking All-Time Ranking
Concepts – Calculating Ethnicity Percentages January 2017 1 2
Proving Native American Ancestry Using DNA December 2012 2 1
Ancestral DNA Percentages – How Much of Them in in You? June 2017 3 5
AutoKinship at GEDmatch by Genetic Affairs February 2022 4
442 Ancient Viking Skeletons Hold DNA Surprises – Does Your Y or Mitochondrial DNA Match? Daily Updates Here September 2020 5
The Origins of Zana of Abkhazia July 2021 6
Full or Half Siblings April 2019 7 15
Ancestry Rearranged the Furniture January 2022 8
DNA from 459 Ancient British Isles Burials Reveals Relationships – Does Yours Match? February 2022 9
DNA Inherited from Grandparents and Great-Grandparents January 2020 10
Ancestry Only Shows Shared Matches of 20 cM and Greater – What That Means & Why It Matters May 2022 11
How Much Indian Do I Have in Me??? June 2015 12 8
Top Ten RootsTech 2022 DNA Sessions + All DNA Session Links March 2022 13
FamilyTreeDNA DISCOVER Launches – Including Y DNA Haplogroup Ages June 2022 14
Ancient Ireland’s Y and Mitochondrial DNA – Do You Match??? November 2020 15

2023 Suggestions

I have a few articles already in the works for 2023, including some surprises. I’ll unveil one very soon.

We will be starting out with:

  • Information about RootsTech where I’ll be giving at least 7 presentations, in person, and probably doing a book signing too. Yes, I know, 7 sessions – what was I thinking? I’ve just missed everyone so very much.
  • An article about how accurately Ancestry’s ThruLines predicts Potential Ancestors and a few ways to prove, or disprove, accuracy.
  • The continuation of the “In Search Of” series.

As always, I’m open for 2023 suggestions.

In the comments, let me know what topics you’d like to see.

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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.

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In Search of…How Am I Related to That Close Match?

My friend recently reached out to me for some help with a close match at Ancestry. Which vendor doesn’t matter – the process for figuring out who my friend is related to her match would be essentially the same at any vendor.

My friend has no idea who the match is, nor how they are related. That match has not replied, nor is any of her information recognizable, such as an account name or photo. She has no tree, so there are literally no clues provided by the match.

We need to turn to science and old-fashioned sleuthing.

This eighth article in the “In Search of…” series steps you through the process I’m stepping my friend through.

This process isn’t difficult, per se, but there are several logical, sequential steps. I strongly recommend you read through this (at least) once, then come back and work through the process if you’re trying to solve a similar mystery.

The “In Search of…” Series

Please note that I’ve written an entire series of “In Search of…” articles that will step you through the search process and help you understand how to unravel your results. If you’re new, reading these, in order, before proceeding, would be a good idea.

  • I introduced the “In Search of” series in the article, DNA: In Search of…New Series Launches.
  • In the second article, DNA: In Search of…What Do You Mean I’m Not Related to My Family? – and What Comes Next? we discussed the discovery that something was amiss when you don’t match a family member that you expect to match, then how to make sure a vial or upload mix-up didn’t happen. Next, I covered the basics of the four kinds of DNA tests you’ll be able to use to solve your mystery.
  • In the third article, In Search of…Vendor Features, Strengths, and Testing Strategies, we discussed testing goals and strategies, including testing with and uploading to multiple autosomal DNA vendors, Y DNA, and mitochondrial DNA testing. We reviewed the vendor’s strengths and the benefits of combining vendor information and resources.
  • In the fourth article, DNA: In Search of…Signs of Endogamy, we discussed the signs of endogamy and various ways to determine if you or your recent ancestors descend from an endogamous population.
  • In the fifth article, DNA: In Search of…Full and Half-Siblings we discussed how to determine if you have a sibling match, if they are a half or full sibling, and how to discern the difference.
  • In the sixth article, Connect Your DNA test, and Others, to Your Tree, I explained how to optimize your DNA tests in order to take advantage of the features offered by each our primary DNA testing vendors.
  • In the seventh article, How to Share DNA Results and Tree Access at Ancestry, I wrote step-by-step instructions for providing access to another person to allow them to view your DNA results, AND to share your tree – which are two different things. If you have a mystery match, and they are willing to allow you access, in essence “to drive,” you can just send them the link to this article that provides detailed instructions. Note that Ancestry has changed the user interface slightly with the rollout of their new “sides” matches, but I can’t provide the new interface screenshots yet because my account has not been upgraded.

Sarah – The Mystery Match

My friend, who I’ll be calling the Tester, matches Sarah (not her name) at 554 cM. At that close level, you don’t have to worry about segments being removed by Timber at Ancestry, so that is an actual cM match level. Timber only removes segments when the match is under 90 cM. Other vendors don’t remove cMs at all.

Ancestry shows the possible relationships at that level as follows:

Some of these relationships can be immediately dismissed in this situation. For example, the Tester knows that Sarah is not her grandchild or great-grandchild.

Our tester does not have any full siblings, or any known half-siblings, but like many genealogists, she is always open-minded. Both of her parents are living, and her father has already tested. Sarah does not match her father. So, this match is on her mother’s side.

It’s obvious that Sarah is not a full sibling, nor is she a half-sibling, based on the cM values, but she might be a child, or grandchild of a maternal half-sibling.

Let’s begin with observations and questions that will help our Tester determine how she and Sarah are related.

  1. It’s clear that IF this is a half-sibling descendant match, it’s on her mother’s side, because Sarah does not match our Tester’s father.
  2. The tester’s mother has six siblings, none of whom have tested directly, but three of whom have children or grandchildren who have tested.
  3. By viewing shared matches, Sarah matches known relatives of BOTH the maternal grandmother AND maternal grandfather of our tester, which means Sarah is NOT the product of an unknown half-sibling of her mother. Remember, Ancestry does not display shared matches of less than 20 cM. Other vendors do not restrict your shared matches.
  4. Ancestry does not provide mitochondrial DNA information, so that cannot be utilized, but could be utilized if this match was at FamilyTreeDNA, and partially utilized in an exclusionary manner if the match was at 23andMe.

DNAPainter

DNAPainter’s Shared cM Tool provides a nice visual display of possible relationships, so I entered the matching cM amount

The returned relationships are similar to Ancestry’s possible relationships.

The grid display shows the possible relationships. Relationships that fall outside of this probability range are muted.

The color shading is by generation, meaning dark grey is through great-great-grandparents, apricot is through great-grandparents, green is through grandparents, grey is through one or both parents, and blue are your own descendants.

Based on known factors, I put a red X in the boxes that can’t apply to Sarah and our Tester after evaluating each relationship. I bracketed the statistically most likely relationships in red, although I must loudly say, “do not ignore those other possibilities.”

Let’s step through the logic which will be different for everyone’s own situation, of course.

  • Age alone eliminates the great and half-great grandparents, aunts, and uncles. They are all deceased and would be well over 100 years old if they were living.
  • The green half relationships are eliminated because we know via shared matches that Sarah matches BOTH of the Tester’s maternal grandparent’s sides.
  • We know that Sarah is not a second cousin because second cousins match only ONE maternal grandparent’s ancestor’s descendants, and Sarah matches both of the tester’s maternal grandparents through their descendants. In other words, Sarah and our Tester both match people who descend from both of the Tester’s maternal grandmother AND grandfather’s lines, which, unless they are related, means Sarah’s closest common ancestor (MCRA – most recent common ancestor) with our Tester are either her maternal grandparents, or her mother.
  • Therefore, we know that Sarah cannot be any of the apricot-colored relationships because she matches BOTH of our Tester’s maternal grandparents. She would only be related through one of the Tester’s maternal grandparents to be related on the apricot level.
  • Sarah cannot be a full great-niece or nephew, or great or great-great niece or nephew because the Tester has no full siblings, confirmed by the fact that Sarah does not match the Tester’s father.
  • We know that Sarah is not the great-grandchild of the Tester, in part due to age, but the definitive scientific ax to that possibility is that Sarah does not match our Tester’s father. (Yes, our Tester does match her father at the appropriate level.)

We know that Sarah is somehow a descendant of BOTH of Tester’s maternal grandparents, so must be in either the green band of relationships, the grey half-relationships, or the blue direct relationships. All of these relationships would be descended from the Tester’s maternal grandparents (plural.)

We’ve eliminated the blue direct relationship because Sarah does not match the Tester’s father. This removes the possibility that the Tester’s children have an unknown great-grandchild, although in this case, age removes that possibility anyway.

This process-of-elimination leaves as possible relationships:

  • Grey band half niece/nephew and half great-niece/nephew, meaning that the Tester has an unknown half-sibling on their mother’s side whose child or grandchild has tested.
  • Green band first cousin which means that the tester descends from one of the Tester’s maternal aunts or uncles. Given that Sarah is not a known child of any of the Tester’s six aunts and uncles, that opens the possibility that her mother’s sibling has a previously unknown child. Three of the Tester’s mother’s siblings are females, and three are males.
  • Green band first cousin once removed is one generation further down the tree, meaning a child of a first cousin.

Using facts we know, we’ve already restricted the possible relationships to four.

Hypothesis and Shared Matches

In situations like this, I use a spreadsheet, create hypothesis scenarios and look for eliminators.

I worked with the Tester to assemble an easy spreadsheet with each of her mother’s siblings in a column, along with their year of birth. All names have been changed.

The hypothesis we are working with is that the Tester’s mother has a previously unknown child and that Sarah is that person’s child or grandchild.

Across the top of our spreadsheet, which you could also simply create as a chart, I’ve written the names of the maternal grandparents.

The Tester’s mother, Susie, is shown in the boxes that are colored red, and her siblings are listed in their birth order. Siblings who have anyone in their line who has tested are shown by colored boxes.

The Tester is shown in red beneath her mother, Susie, and a potential mystery half-sibling is shown beneath Susie.

This is importantthe relationships shown are FROM THE PERSPECTIVE OF THE TESTER.

This means, at far left, with the red arrow, these people at the top, meaning the mother’s siblings are the Tester’s aunts and uncles.

The next generation down are the Tester’s first cousins, followed by the next row, with 1C1R. The cell colors in that column correspond to the DNAPainter generation columns.

In the red “Mother” group, you’ll see that I’ve included that mystery half-sibling and beneath, the relationships that could exist at that same generation level. So, if the mystery half-sibling had a child, that person would be the half-niece/nephew of the Tester.

The cM value pointed to by the arrows, is the cM value at which the TESTER matches that person.

In this case, Ginger’s son, Jacob matches our Tester at 946 cM, which is exactly normal for a first cousin. Ginger’s son, Aaron, has not tested, but his daughter, Crystal, has and matches our Tester at 445 cM.

Three of the Tester’s aunts/uncles, John, Jim, and Elsie are not represented in this matrix, because no one from their line has yet tested. The Tester has contacted members of those families asking if they will accept a testing scholarship.

Analysis Grids

Some of the children of our Tester’s aunts/uncles have tested, and their matches to Sarah are shown in the bottom row in yellow, on the chart below.

Of course, obtaining Sarah’s matching cM information required the Tester to contact her aunts/uncles and cousins to ask them to look at their match to Sarah at Ancestry.

For each set of relationships with Sarah, I’ve prepared a mini-relationship grid below Sarah’s matches with one of the Tester’s aunts/uncles’ descendants.

  • If Sarah is related to the Tester through an unknown half-sibling, Sarah will match the tester more closely than she will match any of the children of the Tester’s aunts and uncles.
  • If Sarah descends through one of the Tester’s aunts’ or uncles’ lines, Sarah will match someone in those lines more closely than our Tester, but we may need to compensate for generations in our analysis.

I pasted the DNAPainter image in the spreadsheet in a convenient place to remind myself of which relationships are possible between our Tester and Sarah, then I created a small grid beneath the Tester’s match to Sarah, who is the yellow row.

Let me explain, beginning with our Tester’s match to Sarah.

Tester’s Match to Sarah

The Tester matches Sarah at 554 cM, which can potentially be a number of different relationships. I’ve listed the possible relationships with the most likely, at 87%, at the top. I have not listed any relationships we’ve positively eliminated, even though they would be scientifically possible.

I can’t do this for our Tester’s Uncle David, because the Tester has not yet heard back from David’s son, Gary, as to how many cMs he shares with Sarah.

Our tester’s aunts, Ginger and Barbara do have descendants who have tested, so let’s evaluate those relationships.

Ginger and Sarah

We know less about Ginger and Sarah than we do about our Tester and Sarah. However, many of the same relationship constraints remain constant.

  • For example, we know that Sarah matches both of Ginger’s grandparents, because Ginger is our tester’s aunt, Susie’s full sibling.
  • Our tester and all of the other family members who have tested match on both maternal grandparents’ sides.
  • Therefore, we also know that the 2C relationships won’t work either because Sarah matches both maternal grandparents.
  • Based on ages, it’s very unlikely that Sarah is a great-grandchild of Ginger’s children, in part, because I’m operating under the assumption that Sarah is old enough to purchase her own test, so not a child. Ancestry’s terms of service require testers to be 18 years of age to purchase or activate a DNA test. Also, Sarah’s test is not managed by someone else.
  • We don’t know about great-nieces and nephews though, because if one of Ginger’s sibling’s children had an unknown child, that person could be Sarah or Sarah’s parent.

Ginger’s son Jacob

Using the closest match in Ginger’s line, her son Jacob, we find the following possibilities using Jacob’s match to Sarah of 284cM.

The DNAPainter grid shows the more distant relationship clearly.

You can quickly determine that Sarah probably does not descend from Ginger’s line, but let’s add this to our spreadsheet for completeness.

You can see that the MOST likely relationship, of the possible relationships based on our known factors, is 1C2R, which is the least likely relationship between our Tester and Sarah. It’s important to note that our Tester and Jacob are in the same generation, so we don’t need to do any compensating for a generational difference.

Comparing those relationships, you can see that the least likely relationship between Sarah and Jacob is much more likely between Sarah and our Tester.

Therefore, we can rule out Ginger’s line as a candidate. Sarah is not a descendant of Ginger.

Let’s move on to Barbara’s line.

Barbara’s Daughter Cindy

This time, we’re going to do a bit of inferring because we do have a generational difference.

Barbara’s granddaughter, Mary, has tested and matches Sarah at 230 cM. While we know that Sarah probably wouldn’t match Mary’s mother, Cindy, at exactly double that, 460 cM, it would certainly be close.

So, for purposes of this comparison, I’m using 460 cM for Sarah to match Cindy.

That makes this comparison in the same generation as Ginger and our Tester to Sarah. We are comparing apples to apples and not apples to half an apple (an apple once removed, technically, but I digress.) 😊

You can see that this analysis is MUCH closer to the cM amounts and relationship possibilities of Sarah and our Tester.

Here are the possible relationships of Sarah and Cindy, with the most likely being boxed in red.

Where Are We?

Here is my completed spreadsheet, so far, less the two DNAPainter graphs for Ginger and Barbara’s lines.

To date, we’ve eliminated Ginger as Sarah’s ancestor.

Both Susie, the mother of our Tester, and Susie’s sister Barbara are still candidates to have an unknown child based on DNA, or one of their children possibly having an unknown child.

Of course, we still have one more sister, Elsie, and those three silent brothers sitting over there. It’s much easier for a male to have an unknown child than a female. By unknown, in this situation, I mean truly unknown, not hidden.

What’s Needed?

Of course, what we really need is tests from each of Susie’s siblings, but that’s not going to happen. What can we potentially do with what we have, how, and why?

Our Tester can refine these results in a number of ways.

  • Talk to living siblings or other family members and tactfully ask what they know about the four women during their reproductive years. Were they missing, off at school, visiting “aunts” in another location, separated from a spouse, etc.?
  • Check to see if Sarah shared her ethnicity results (View match, then click on “Ethnicity.”) If Sarah has a significant ethnicity that is impossible to confuse, this might be significant. For example, if Sarah is 50% Korean, and one of Susie’s brothers served in Korea, that makes him a prime candidate.
  • If possible, ask John, David, Jim, Ginger, Barbara, and Elsie to take DNA tests themselves. The best test is ALWAYS the oldest generation because their DNA is not yet divided in subsequent generations.
  • If that’s not possible, find a child or grandchild of Elsie, Jim, and John to test.
  • The Tester needs to find out how closely David’s son, Gary matches Sarah, then perform the same analysis that we stepped through above.
  • Ask Ginger’s son, Jacob to see if Sarah also shares matches with the closest family members of the known father of Ginger’s children. One of Ginger’s children could have had an unknown child. This is unlikely, based on what we’ve already determined about Sarah’s match level to Jacob, but it’s worth asking.
  • Ask Barbara’s granddaughter, Mary, to see if she and Sarah share matches with the closest family members of the known father of Barbara’s children. This scenario is much more likely.
  • If the answer is yes to either of the last two questions, we have identified which line Sarah descends from, because she can only descend from both Barbara AND the father of her children if Sarah descends from that couple.
  • If the answer is no, we’ve only eliminated full siblings to Ginger and Barbara’s children, not half-siblings.
  • If our Tester can make contact with Gary, ask him if he and Sarah share matches with David’s wife’s line. One of David’s children could have an unknown child.
  • If our Tester can actually make contact with Sarah, and if Sarah is willing and interested, our Tester can create a list of people to look for in her matches – for example, the spouses’ lines of all of Susie’s siblings. If Sarah matches NONE of the spouses’ lines, then one of Susie’s siblings (our Tester’s aunts/uncles,) or Susie’s mother, has an unknown child. However, if Sarah is a novice tester or genealogist, she might well be quite overwhelmed with understanding how to perform these searches. She may already be overwhelmed by discovering that she doesn’t match who she expected to match. Or, she may already know the answer to this question.
  • It would be easier if Sarah granted our Tester access to her DNA results to sort through all of these possibilities, but that’s not something I would expect a stranger to do, especially if this result is something Sarah wasn’t expecting.

I wrote instructions for providing access to DNA results in the article, How to Share DNA Results and Tree Access at Ancestry.

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DNA: In Search of…Full and Half-Siblings

This is the fifth article 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 identify ancestors further back in time as well.

Please note that if a family member has tested and you do NOT see their results, ask them to verify that they have chosen to allow matching and for other people to view them in their match list. That process varies at different vendors.

You can also ask if they can see you in their results.

All Parties Need to Test

Searching for unknown siblings isn’t exactly searching, because to find them, they, themselves, or their descendant(s) must have taken a DNA test at the same vendor where you tested or uploaded a DNA file.

You may know through any variety of methods that they exist, or might exist, but if they don’t take a DNA test, you can’t find them using DNA. This might sound obvious, but I see people commenting and not realizing that the other sibling(s) must test too – and they may not have.

My first questions when someone comments in this vein are:

  1. Whether or not they are positive their sibling actually tested, meaning actually sent the test in to the vendor, and it was received by the testing company. You’d be surprised how many tests are living in permanent residence on someone’s countertop until it gets pushed into the drawer and forgotten about.
  2. If the person has confirmed that their sibling has results posted. They may have returned their test, but the results aren’t ready yet or there was a problem.
  3. AND that both people have authorized matching and sharing of results. Don’t hesitate to reach out to your vendor’s customer care if you need help with this.

Sibling Scenarios

The most common sibling scenarios are when one of two things happens:

  • A known sibling tests, only to discover that they don’t match you in the full sibling range, or not at all, when you expected they would
  • You discover a surprise match in the full or half-sibling range

Let’s talk about these scenarios and how to determine:

  • If someone is a sibling
  • If they are a full or half-sibling
  • If a half-sibling, if they descend from your mother or father

As with everything else genetic, we’ll be gathering and analyzing different pieces of evidence along the way.

Full and Half-Siblings

Just to make sure we are all on the same page:

  • A full sibling is someone who shares both parents with you.
  • A half-sibling is someone who shares one parent with you, but not the other parent.
  • A step-sibling is someone who shares no biological parents with you. This situation occurs when your parent marries their parent, after you are both born, and their parent becomes your step-parent. You share neither of your biological parents with a step-sibling, so you share no DNA and will not show up on each other’s match lists.
  • A three-quarters sibling is someone with whom you share one parent, but two siblings are the other parent. For example, you share the same mother, but one brother fathered you, and your father’s brother fathered your sibling. Yes, this can get very messy and is almost impossible for a non-professional to sort through, if even then. (This is not a solicitation. I do not take private clients.) We will not be addressing this situation specifically.

Caution

With any search for unknown relatives, you have no way of knowing what you will find.

In one’s mind, there are happy reunions, but you may experience something entirely different. Humans are human. Their stories are not always happy or rosy. They may have made mistakes they regret. Or they may have no regrets about anything.

Your sibling may not know about you or the situation under which you, or they, were born. Some women were victims of assault and violence, which is both humiliating and embarrassing. I wrote about difficult situations, here.

Your sibling or close family member may not be receptive to either you, your message, or even your existence. Just be prepared, because the seeking journey may not be pain-free for you or others, and may not culminate with or include happy reunions.

On the other hand, it may.

Please step back and ponder a bit about the journey you are about to undertake and the possible people that may be affected, and how. This box, once opened, cannot be closed again. Be sure you are prepared.

On the other hand, sometimes that box lid pops off, and the information simply falls in your lap one day when you open your match list, and you find yourself sitting there, in shock, staring at a match, trying to figure out what it all means.

Congratulations, You Have a Sibling!

This might not be exactly what runs through your mind when you see that you have a very close match that you weren’t expecting.

The first two things I recommend when making this sort of discovery, after a few deep breaths, a walk, and a cup of tea, are:

  • Viewing what the vendor says
  • Using the DNAPainter Shared cM Relationship Chart

Let’s start with DNAPainter.

DNAPainter

DNAPainter provides a relationship chart, here, based on the values from the Shared cM Project.

You can either enter a cM amount or a percentage of shared DNA. I prefer the cM amount, but it doesn’t really matter.

I’ll enter 2241 cM from a known half-sibling match. To enter a percent, click on the green “enter %.”

As you can see, statistically speaking, this person is slightly more likely to be a half-sibling than they are to be a full sibling. In reality, they could be either.

Looking at the chart below, DNAPainter highlights the possible relationships from the perspective of “Self.”

The average of all the self-reported relationships is shown, on top, so 2613 for a full sibling. The range is shown below, so 1613-3488 for a full sibling.

In this case, there are several possibilities for two people who share 2241 cM of DNA.

I happen to know that these two people are half-siblings, but if I didn’t, it would be impossible to tell from this information alone.

The cM range for full siblings is 1613-3488, and the cM range for half-siblings is 1160-2436.

  • The lower part of the matching range, from 1160-1613 cM is only found in half-siblings.
  • The portion of the range from 1613-2436 cM can be either half or full siblings.
  • The upper part of the range, from 2436-3488 cM is only found in full siblings.

If your results fall into the center portion of the range, you’re going to need to utilize other tools. Fortunately, we have several.

If you’ve discovered something unexpected, you’ll want to verify using these tools, regardless. Use every tool available. Ranges are not foolproof, and the upper and lower 10% of the responses were removed as outliers. You can read more about the shared cM Project, here and here.

Furthermore, people may be reporting some half-sibling relationships as full sibling relationships, because they don’t expect to be half-siblings, so the ranges may be somewhat “off.”

Relationship Probability Calculator

Third-party matching database, GEDmatch, provides a Relationship Probability Calculator tool that is based on statistical probability methods without compiled user input. Both tools are free, and while I haven’t compared every value, both seem to be reasonably accurate, although they do vary somewhat, especially at the outer ends of the ranges.

When dealing with sibling matches, if you are in all four databases, GEDmatch is a secondary resource, but I will include GEDmatch when they have a unique tool as well as in the summary table. Some of your matches may be willing to upload to GEDmatch if the vendor where you match doesn’t provide everything you need and GEDmatch has a supplemental offering.

Next, let’s look at what the vendors say about sibling matches.

Vendors

Each of the major vendors reports sibling relationships in a slightly different way.

Sibling Matches at Ancestry

Ancestry reports sibling relationships as Sister or Brother, but they don’t say half or full.

If you click on the cM portion of the link, you’ll see additional detail, below

Ancestry tells you that the possible relationships are 100% “Sibling.” The only way to discern the difference between full and half is by what’s next.

If the ONLY relationship shown is Sibling at 100%, that can be interpreted to mean this person is a full sibling, and that a half-sibling or other relationship is NOT a possibility.

Ancestry never stipulates full or half.

The following relationship is a half-sibling at Ancestry.

Ancestry identifies that possible range of relationships as “Close Family to First Cousin” because of the overlaps we saw in the DNAPainter chart.

Clicking through shows that there is a range of possible relationships, and Ancestry is 100% sure the relationship is one of those.

DNAPainter agrees with Ancestry except includes the full-sibling relationship as a possibility for 1826 cM.

Sibling Matches at 23andMe

23andMe does identify full versus half-siblings.

DNAPainter disagrees with 23andMe and claims that anyone who shares 46.2% of their DNA is a parent/child.

However, look at the fine print. 23andMe counts differently than any of the other vendors, and DNAPainter relies on the Shared cM Project, which relies on testers entering known relationship matching information. Therefore, at any other vendor, DNAPainter is probably exactly right.

Before we understand how 23andMe counts, we need to understand about half versus fully identical segments.

To determine half or full siblings, 23andMe compares two things:

  1. The amount of shared matching DNA between two people
  2. Fully Identical Regions (FIR) of DNA compared to Half Identical Regions (HIR) of DNA to determine if any of your DNA is fully identical, meaning some pieces of you and your sibling’s DNA is exactly the same on both your maternal and paternal chromosomes.

Here’s an example on any chromosome – I’ve randomly selected chromosome 12. Which chromosome doesn’t matter, except for the X, which is different.

Your match isn’t broken out by maternal and paternal sides. You would simply see, on the chromosome browser, that you and your sibling match at these locations, above.

In reality, though, you have two copies of each chromosome, one from Mom and one from Dad, and so does your sibling.

In this example, Mom’s chromosome is visualized on top, and Dad’s is on the bottom, below, but as a tester, you don’t know that. All you know is that you match your sibling on all of those blue areas, above.

However, what’s actually happening in this example is that you are matching your sibling on parts of your mother’s chromosome and parts of your father’s chromosome, shown above as green areas

23andMe looks at both copies of your chromosome, the one you inherited from Mom, on top, and Dad, on the bottom, to see if you match your sibling on BOTH your mother’s and your father’s chromosomes in that location.

I’ve boxed the green matching areas in purple where you match your sibling fully, on both parents’ chromosomes.

If you and your sibling share both parents, you will share significant amounts of the same DNA on both copies of the same chromosomes, meaning maternal and paternal. In other words, full siblings share some purple fully identical regions (FIR) of DNA with each other, while half-siblings do not (unless they are also otherwise related) because half-siblings only share one parent with each other. Their DNA can’t be fully identical because they have a different parent that contributed the other copy of their chromosome.

Total Shared DNA Fully Identical DNA from Both Parents
Full Siblings ~50% ~25%
Half Siblings ~25% 0
  • Full siblings are expected to share about 50% of the same DNA. In other words, their DNA will match at that location. That’s all the green boxed locations, above.
  • Full siblings are expected to share about 25% of the same DNA from BOTH parents at the same location on BOTH copies of their chromosomes. These are fully identical regions and are boxed in purple, above.

You’ll find fully identical segments about 25% of the time in full siblings, but you won’t find fully identical segments in half-siblings. Please note that there are exceptions for ¾ siblings and endogamous populations.

You can view each match at 23andMe to see if you have any completely identical regions, shown in dark purple in the top comparison of full siblings. Half siblings are shown in the second example, with less total matching DNA and no FIR or completely identical regions.

Please note that your matching amount of DNA will probably be higher at 23andMe than at other companies because:

  • 23andMe includes the X chromosome in the match totals
  • 23andMe counts fully identical matching regions twice. For full siblings, that’s an additional 25%

Therefore, a full sibling with an X match will have a higher total cM at 23andMe than the same siblings elsewhere because not only is the X added into the total, the FIR match region is added a second time too.

Fully Identical Regions (FIR) and Half Identical Regions (HIR) at GEDmatch

At GEDMatch, you can compare two people to each other, with an option to display the matching information and a painted graphic for each chromosome that includes FIR and HIR.

If you need to know if you and a match share fully identical regions and you haven’t tested at 23andMe, you can both upload your DNA data file to GEDmatch and use their One to One Autosomal DNA Comparison.

On the following page, simply enter both kit numbers and accept the defaults, making sure you have selected one of the graphics options.

While GEDmatch doesn’t specifically tell you whether someone is a full or half sibling, you can garner additional information about the relationship based on the graphic at GEDmatch.

GEDMatch shows both half and fully identical regions.

The above match is between two full siblings using a 7 cM threshold. The blue on the bottom bar indicates a match of 7 cM or larger. Black means no match.

The green regions in the top bar indicate places where these two people carry the same DNA on both copies of their chromosome 1. This means that both people inherited the same DNA from BOTH parents on the green segments.

In the yellow regions, the siblings inherited the same DNA from ONE parent, but different DNA in that region from the other parent. They do match each other, just on one of their chromosomes, not both.

Without a tool like this to differentiate between HIR and FIR, you can’t tell if you’re matching someone on one copy of your chromosome, or on both copies.

In the areas marked with red on top, which corresponds to the black on the bottom band, these two siblings don’t match each other because they inherited different DNA from both parents in that region. The yellow in that region is too scattered to be significant.

Full siblings generally share a significant amount of FIR, or fully identical regions of DNA – about 25%.

Half siblings will share NO significant amount of FIR, although some will be FIR on very small, scattered green segments simply by chance, as you can see in the example, below.

This half-sibling match shares no segments large enough to be a match (7 cM) in the black section. In the blue matching section, only a few small green fragments of DNA match fully, which, based on the rest of that matching segment, must be identical by chance or misreads. There are no significant contiguous segments of fully identical DNA.

When dealing with full or half-siblings, you’re not interested in small, scattered segments of fully identical regions, like those green snippets on chromosome 6, but in large contiguous sections of matching DNA like the chromosome 1 example.

GEDmatch can help when you match when a vendor does not provide FIR/HIR information, and you need additional assistance.

Next, let’s look at full and half-siblings at FamilyTreeDNA

Sibling Matches at FamilyTreeDNA

FamilyTreeDNA does identify full siblings.

Relationships other than full siblings are indicated by a range. The two individuals below are both half-sibling matches to the tester.

The full range when mousing over the relationship ranges is shown below.

DNAPainter agrees except also gives full siblings as an option for the two half-siblings.

FamilyTreeDNA also tells you if you have an X match and the size of your X match.

We will talk about X matching in a minute, which, when dealing with sibling identification, can turn out to be very important.

Sibling Matches at MyHeritage

MyHeritage indicates brother or sister for full siblings

MyHeritage provides other “Estimated relationships” for matches too small to be full siblings.

DNAPainter’s chart agrees with this classification, except adds additional relationship possibilities.

Be sure to review all of the information provided by each vendor for close relationships.

View Close Known Relationships

The next easiest step to take is to compare your full or half-sibling match to known close family members from your maternal and paternal sides, respectively. The closer the family members, the better.

It’s often not possible to determine if someone is a half sibling or a full sibling by centiMorgans (cMs) alone, especially if you’re searching for unknown family members.

Let’s start with the simplest situation first.

Let’s say both of your parents have tested, and of course, you match both of them as parents.

Your new “very close match” is in the sibling range.

The first thing to do at each vendor is to utilize that vendor’s shared matches tool and see whether your new match matches one parent, or both.

Here’s an example.

Close Relationships at FamilyTreeDNA

This person has a full sibling match, but let’s say they don’t know who this is and wants to see if their new sibling matches one or both of their parents.

Select the match by checking the box to the left of the match name, then click on the little two-person icon at far right, which shows “In Common” matches

You can see on the resulting shared match list that both of the tester’s parents are shown on the shared match list.

Now let’s make this a little more difficult.

No Parents, No Problem

Let’s say neither of your parents has tested.

If you know who your family is and can identify your matches, you can see if the sibling you match matches other close relatives on both or either side of your family.

You’ll want to view shared matches with your closest known match on both sides of your tree, beginning with the closest first. Aunts, uncles, first cousins, etc.

You will match all of your family members through second cousins, and 90% of your third cousins. You can view additional relationship percentages in the article, How Much of Them is in You?.

I recommend, for this matching purpose, to utilize 2nd cousins and closer. That way you know for sure if you don’t share them as a match with your sibling, it’s because the sibling is not related on that side of the family, not because they simply don’t share any DNA due to their distance.

In this example, you have three sibling matches. Based on your and their matches to the same known first and second cousins, you can see that:

  • Sibling 1 is your full sibling, because you both match the same maternal and paternal first and second cousins
  • Sibling 2 is your paternal half-sibling because you both match paternal second cousins and closer, but not maternal cousins.
  • Sibling 3 is your maternal half-sibling because you both match maternal second cousins and closer, but not paternal cousins.

Close Relationships at Ancestry

Neither of my parents have tested, but my first cousin on my mother’s side has. Let’s say I have a suspected sibling or half-sibling match, so I click on the match’s name, then on Shared Matches.

Sure enough, my new match also matches my first cousin that I’ve labeled as “on my mother’s side.”

If my new match in the sibling range also matches my second cousins or closer on my father’s side, the new match is a full sibling, not a half-sibling.

Close Relationships at MyHeritage

Comparing my closest match provided a real surprise. I wonder if I’ve found a half-sibling to my mother.

Now, THIS is interesting.

Hmmm. More research is needed, beginning with the age of my match. MyHeritage provides ages if the MyHeritage member authorizes that information to be shared.

Close Relationships at 23andMe

Under DNA Relatives, click on your suspected sibling match, then scroll down and select “Find Relatives in Common.”

The Relatives in Common list shows people that match both of you.

The first common match is very close and a similar relationship to my closest match on my father’s side. This would be expected of a sibling. I have no common matches with this match to anyone on my mother’s side, so they are only related on my father’s side. Therefore they are a paternal half-sibling, not a full sibling.

More Tools Are Available

Hopefully, by now, you’ve been able to determine if your mystery match is a sibling, and if so, if they are a half or full sibling, and through which parent.

We have some additional tools that are relevant and can be very informative in some circumstances. I suggest utilizing these tools, even if you think you know the answer.

In this type of situation, there’s no such thing as too much information.

X Matching

X matching, or lack thereof, may help you determine how you are related to someone.

There are two types of autosomal DNA. The X chromosome versus chromosomes 1-22. The X chromosome (number 23) has a unique inheritance path that distinguishes it from your other chromosomes.

The X chromosome inheritance path also differs between men and women.

Here’s my pedigree chart in fan form, highlighting the ancestors who may have contributed a portion of their X chromosome to me. In the closest generation, this shows that I inherited an X chromosome from both of my parents, and who in each of their lines could have contributed an X to them.

The white or uncolored positions, meaning ancestors, cannot contribute any portion of an X chromosome to me based on how the X chromosome is inherited.

You’ll notice that my father inherited none of his X chromosome from any of his paternal ancestors, so of course, I can’t inherit what he didn’t inherit. There are a very limited number of ancestors on my father’s side whom I can inherit any portion of an X chromosome from.

Men receive their Y chromosome from their fathers, so men ONLY receive an X chromosome from their mother.

Therefore, men MUST pass their mother’s X chromosome on to their female offspring because they don’t have any other copy of the X chromosome to pass on.

Men pass no X chromosome to sons.

We don’t need to worry about a full fan chart when dealing with siblings and half-siblings.

We only need to be concerned with the testers plus one generation (parents) when utilizing the X chromosome in sibling situations.

These two female Disney Princesses, above, are full siblings, and both inherited an X chromosome from BOTH their mother and father. However, their father only has one X (red) chromosome to give them, so the two females MUST match on the entire red X chromosome from their father.

Their mother has two X chromosomes, green and black, to contribute – one from each of her parents.

The full siblings, Melody, and Cinderella:

  • May have inherited some portion of the same green and black X chromosomes from their mother, so they are partial matches on their mother’s X chromosome.
  • May have inherited the exact same full X chromosome from their mother (both inherited the entire green or both inherited the entire black), so they match fully on their mother’s X chromosome.
  • May have inherited the opposite X from different maternal grandparents. One inherited the entire green X and one inherited the entire black X, so they don’t match on their mother’s X chromosome.

Now, let’s look at Cinderella, who matches Henry.

This female and male full sibling match can’t share an X chromosome on the father’s side, because the male’s father doesn’t contribute an X chromosome to him. The son, Henry, inherited a Y chromosome instead from his father, which is what made them males.

Therefore, if a male and female match on the X chromosome, it MUST be through HIS mother, but could be through either of her parents. In a sibling situation, an X match between a male and female always indicates the mother.

In the example above, the two people share both of their mother’s X chromosomes, so are definitely (at least) maternally related. They could be full siblings, but we can’t determine that by the X chromosome in this situation, with males.

However, if the male matches the female on HER father’s X chromosome, there a different message, example below.

You can see that the male is related to the female on her father’s side, where she inherited the entire magenta X chromosome. The male inherited a portion of the magenta X chromosome from his mother, so these two people do have an X match. However, he matches on his mother’s side, and she matches on her father’s side, so that’s clearly not the same parent.

  • These people CAN NOT be full siblings because they don’t match on HER mother’s side too, which would also be his mother’s side if they were full siblings.
  • They cannot be maternal half-siblings because their X DNA only matches on her father’s side, but they wouldn’t know that unless she knew which side was which based on share matches.
  • They cannot be paternal half-siblings because he does not have an X chromosome from his father.

They could, however, be uncle/aunt-niece/nephew or first cousins on his mother’s side and her father’s side. (Yes, you’re definitely going to have to read this again if you ever need male-female X matching.)

Now, let’s look at X chromosome matching between two males. It’s a lot less complicated and much more succinct.

Neither male has inherited an X chromosome from their father, so if two males DO match on the X, it MUST be through their mother. In terms of siblings, this would mean they share the same mother.

However, there is one slight twist. In the above example, you can see that the men inherited a different proportion of the green and black X chromosomes from their common mother. However, it is possible that the mother could contribute her entire green X chromosome to one son, Justin in this example, and her entire black X chromosome to Henry.

Therefore, even though Henry and Justin DO share a mother, their X chromosome would NOT match in this scenario. This is rare but does occasionally happen.

Based on the above examples, the X chromosome may be relevant in the identification of full or half siblings based on the sexes of the two people who otherwise match at a level indicating a full or half-sibling relationship.

Here’s a summary chart for sibling X matching.

X Match Female Male
Female Will match on shared father’s full X chromosome, mother’s X is the same rules as chromosomes 1-22 Match through male’s mother, but either of female’s parents. If the X match is not through the female’s mother, they are not full siblings nor maternal half-siblings. They cannot have an X match through the male’s father. They are either full or half-siblings through their mother if they match on both of their mother’s side. If they match on his mother’s side, and her father’s side, they are not siblings but could be otherwise closely related.
Male Match through male’s mother, but either of female’s parents. If the X match is not through the female’s mother, they are not full siblings nor maternal half-siblings. They cannot have an X match through the male’s father. They are either full or half-siblings through their mother if they match on both or their mother’s side. If they match on his mother’s side, and her father’s side, they are not siblings but could be otherwise closely related. Both males are related on their mother’s side – either full or half-siblings.

Here’s the information presented in a different way.

DOES match X summary:

  • If a male DOES match a female on the X, he IS related to her through HIS mother’s side, but could match her on her mother or father’s side. If their match is not through her mother, then they are not full siblings nor maternal half-siblings. They cannot match through his father, so they cannot be paternal half-siblings.
  • If a female DOES match a female on the X, they could be related on either side and could be full or half-siblings.
  • If a male DOES match a male on the X, they ARE both related through their mother. They may also be related on their father’s side, but the X does not inform us of that.

Does NOT match X summary:

  • If a male does NOT match a female on the X, they are NOT related through HIS mother and are neither full siblings nor maternal half-siblings. Since a male does not have an X chromosome from his father, they cannot be paternal half-siblings based on an X match.
  • If a male does NOT match a male, they do NOT share a mother.
  • If a female does NOT match another female on the X, they are NOT full siblings and are NOT half-siblings on their paternal side. Their father only has one X chromosome, and he would have given the same X to both daughters.

Of the four autosomal vendors, only 23andMe and FamilyTreeDNA report X chromosome results and matching, although the other two vendors, MyHeritage and Ancestry, include the X in their DNA download file so you can find X matches with those files at either FamilyTreeDNA or GEDMatch if your match has or will upload their file to either of those vendors. I wrote step-by-step detailed download/upload instructions, here.

X Matching at FamilyTreeDNA

In this example from FamilyTreeDNA, the female tester has discovered two half-sibling matches, both through her father. In the first scenario, she matches a female on the full X chromosome (181 cM). She and her half-sibling MUST share their father’s entire X chromosome because he only had one X, from his mother, to contribute to both of his daughters.

In the second match to a male half-sibling, our female tester shares NO X match because her father did not contribute an X chromosome to his son.

If we didn’t know which parents these half-sibling matches were through, we can infer from the X matching alone that the male is probably NOT through the mother.

Then by comparing shared matches with each sibling, Advanced Matches, or viewing the match Matrix, we can determine if the siblings match each other and are from the same or different sides of the family.

Under Additional Tests and Tools, Advanced Matching, FamilyTreeDNA provides an additional tool that can show only X matches combined with relationships.

Of course, you’ll need to view shared matches to see which people match the mother and/or match the father.

To see who matches each other, you’ll need to use the Matrix tool.

At FamilyTreeDNA, the Matrix, located under Autosomal DNA Results and Tools, allows you to select your matches to see if they also match each other. If you have known half-siblings, or close relatives, this is another way to view relationships.

Here’s an example using my father and two paternal half-siblings. We can see that the half-siblings also match each other, so they are (at least) half-siblings on the paternal side too.

If they also matched my mother, we would be full siblings, of course.

Next, let’s use Y DNA and mitochondrial DNA.

Y DNA and Mitochondrial DNA

In addition to autosomal DNA, we can utilize Y DNA and mitochondrial DNA (mtDNA) in some cases to identify siblings or to narrow or eliminate relationship possibilities.

Given that Y DNA and mitochondrial DNA both have distinctive inheritance paths, full and half-siblings will, or will not, match under various circumstances.

Y DNA

Y DNA is passed intact from father to son, meaning it’s not admixed with any of the mother’s DNA. Daughters do not inherit Y DNA from their father, so Y DNA is only useful for male-to-male comparisons.

Two types of Y DNA are used for genealogy, STR markers for matching, and haplogroups, and both are equally powerful in slightly different ways.

Y DNA at FamilyTreeDNA

Men can order either 37 or 111 STR marker tests, or the BIg Y which provides more than 700 markers and more. FamilyTreeDNA is the only one of the vendors to offer Y DNA testing that includes STR markers and matching between men.

Men who order these tests will be compared for matching on either 37, 111 or 700 STR markers in addition to SNP markers used for haplogroup identification and assignment.

Fathers will certainly match their sons, and paternal line brothers will match each other, but they will also match people more distantly related.

However, if two men are NOT either full or half siblings on the paternal side, they won’t match at 111 markers.

If two men DON’T match, especially at high marker levels, they likely aren’t siblings. The word “likely” is in there because, very occasionally, a large deletion occurs that prevents STR matching, especially at lower levels.

Additionally, men who take the 37 or 111 marker test also receive an estimated haplogroup at a high level for free, without any additional testing.

However, if men take the Big Y-700 test, they not only will (or won’t) match on up to 700 STR markers, they will also receive a VERY refined haplogroup via SNP marker testing that is often even more sensitive in terms of matching than STR markers. Between these two types of markers, Y DNA testing can place men very granularly in relation to other men.

Men can match in two ways on Y DNA, and the results are very enlightening.

If two men match on BOTH their most refined haplogroup (Big Y test) AND STR markers, they could certainly be siblings or father/son. They could also be related on the same line for another reason, such as known or unknown cousins or closer relationships like uncle/nephew. Of course, Y DNA, in addition to autosomal matching, is a powerful combination.

Conversely, if two men don’t have a similar or close haplogroup, they are not a father and son or paternal line siblings.

FamilyTreeDNA offers both inexpensive entry-level testing (37 and 111 markers) and highly refined advanced testing of most of the Y chromosome (Big Y-700), so haplogroup assignments can vary widely based on the test you take. This makes haplogroup matching and interpretation a bit more complex.

For example, haplogroups R-M269 and I-BY14000 are not related in thousands of years. One is haplogroup R, and one is haplogroup I – completely different branches of the Y DNA tree. These two men won’t match on STR markers or their haplogroup.

However, because FamilyTreeDNA provides over 50,000 different haplogroups, or tree branches, for Big Y testers, and they provide VERY granular matching, two father/son or sibling males who have BOTH tested at the Big Y-700 level will have either the exact same haplogroup, or at most, one branch difference on the tree if a mutation occurred between father and son.

If both men have NOT tested at the Big Y-700 level, their haplogroups will be on the same branch. For example, a man who has only taken a 37/111 marker STR test may be estimated at R-M269, which is certainly accurate as far as it goes.

His sibling who has taken a Big Y test will be many branches further downstream on the tree – but on the same large haplogroup R-M269 branch. It’s essential to pay attention to which tests a Y DNA match has taken when analyzing the match.

The beauty of the two kinds of tests is that even if one haplogroup is very general due to no Big Y test, their STR markers should still match. It’s just that sometimes this means that one hand is tied behind your back.

Y DNA matching alone can eliminate the possibility of a direct paternal line connection, but it cannot prove siblingship or paternity alone – not without additional information.

The Advanced Matching tool will provide a list of matches in all categories selected – in this case, both the 111 markers and the Family Finder test. You can see that one of these men is the father of the tester, and one is the full sibling.

You can view haplogroup assignments on the public Y DNA tree, here. I wrote about using the public tree, here.

In addition, recently, FamilyTreeDNA launched the new Y DNA Discover tool, which explains more about haplogroups, including their ages and other fun facts like migration paths along with notable and ancient connections. I wrote about using the Discover tool, here.

Y DNA at 23andMe

Testers receive a base haplogroup with their autosomal test. 23andMe tests a limited number of Y DNA SNP locations, but they don’t test many, and they don’t test STR markers, so there is no Y DNA matching and no refined haplogroups.

You can view the haplogroups of your matches. If your male sibling match does NOT share the same haplogroup, the two men are not paternal line siblings. If two men DO share the same haplogroup, they MIGHT be paternal siblings. They also might not.

Again, autosomal close matching plus haplogroup comparisons include or exclude paternal side siblings for males.

Paternal side siblings at 23andMe share the same haplogroup, but so do many other people. These two men could be siblings. The haplogroups don’t exclude that possibility. If the haplogroups were different, that would exclude being either full or paternal half-siblings.

Men can also compare their mitochondrial DNA to eliminate a maternal relationship.

These men are not full siblings or maternal half-siblings. We know, unquestionably, because their mitochondrial haplogroups don’t match.

23andMe also constructs a genetic tree, but often struggles with close relative placement, especially when half-relationships are involved. I do not recommend relying on the genetic tree in this circumstance.

Mitochondrial DNA

Mitochondrial DNA is passed from mothers to all of their children, but only females pass it on. If two people, males or females, don’t match on their mitochondrial DNA test, with a couple of possible exceptions, they are NOT full siblings, and they are NOT maternal half-siblings.

Mitochondrial DNA at 23andMe

23andMe provides limited, base mitochondrial haplogroups, but no matching. If two people don’t have the same haplogroup at 23andMe, they aren’t full or maternal siblings, as illustrated above.

Mitochondrial DNA at FamilyTreeDNA

FamilyTreeDNA provides both mitochondrial matching AND a much more refined haplogroup. The full sequence test (mtFull), the only version sold today, is essential for reliable comparisons.

Full siblings or maternal half-siblings will always share the same haplogroup, regardless of their sex.

Generally, a full sibling or maternal half-sibling match will match exactly at the full mitochondrial sequence (FMS) level with a genetic distance of zero, meaning fully matching and no mismatching mutations.

There are rare instances where maternal siblings or even mothers and children do not match exactly, meaning they have a genetic distance of greater than 0, because of a mutation called a heteroplasmy.

I wrote about heteroplasmies, here.

Like Y DNA, mitochondrial DNA cannot identify a sibling or parental relationship without additional evidence, but it can exclude one, and it can also provide much-needed evidence in conjunction with autosomal matching. The great news is that unlike Y DNA, everyone has mitochondrial DNA and it comes directly from their mother.

Once again, FamilyTreeDNA’s Advanced Matching tool provides a list of people who match you on both your mitochondrial DNA test and the Family Finder autosomal test, including transfers/uploads, and provides a relationship.

You can see that our tester matches both a full sibling and their mother. Of course, a parent/child match could mean that our tester is a female and one of her children, of either sex, has tested.

Below is an example of a parent-child match that has experienced a heteroplasmy.

Based on the comparison of both the mitochondrial DNA test, plus the autosomal Family Finder test, you can verify that this is a close family relationship.

You can also eliminate potential relationships based on the mitochondrial DNA inheritance path. The mitochondrial DNA of full siblings and maternal half-siblings will always match at the full sequence and haplogroup level, and paternal half-siblings will never match. If paternal half-siblings do match, it’s happenstance or because of a different reason.

Sibling Summary and Checklist

I’ve created a quick reference checklist for you to use when attempting to determine whether or not a match is a sibling, and, if so, whether they are half or full siblings. Of course, these tools are in addition to the DNAPainter Shared cM Tool and GEDmatch’s Relationship Predictor Calculator.

FamilyTreeDNA Ancestry 23andMe MyHeritage GEDmatch
Matching Yes Yes Yes Yes Yes
Shared Matches Yes – In Common With Yes – Shared Matches Yes – Relatives in Common Yes – Review DNA Match Yes – People who match both or 1 of 2 kits
Relationship Between Shared Matches No No No Yes, under shared match No
Matches Match Each Other* Yes, Matrix No Yes, under “View DNA details,” then, “compare with more relatives” Partly, through triangulation Yes, can match any kits
Full Siblings Yes Sibling, implies full Yes Brother, Sister, means full No
Half Siblings Sibling, Uncle/Aunt-Niece/Nephew, Grandparent-Grandchild Close Family – 1C Yes Half sibling, aunt/uncle-niece-nephew No
Fully Identical Regions (FIR) No No Yes No Yes
Half Identical Regions (HIR) No No Yes No Yes
X matching Yes No Yes No Yes
Unusual Reporting or Anomalies No No, Timber is not used on close relationships X match added into total, FIR added twice No Matching amount can vary from vendors
Y DNA Yes, STRs, refined haplogroups, matching No High-level haplogroup only, no matching No No, only if tester enters haplogroup manually
Mitochondrial DNA Yes, full sequence, matching, refined haplogroup No High-level haplogroup only, no matching No No, only if tester enters haplogroup manually
Combined Tools (Autosomal, X, Y, mtDNA) Yes No No No No

*Autoclusters through Genetic Affairs show cluster relationships of matches to the tester and to each other, but not all matches are included, including close matches. While this is a great tool, it’s not relevant for determining close and sibling relationships. See the article, AutoClustering by Genetic Affairs, here.

Additional Resources

Some of you may be wondering how endogamy affects sibling numbers.

Endogamy makes almost everything a little more complex. I wrote about endogamy and various ways to determine if you have an endogamous heritage, here.

Please note that half-siblings with high cM matches also fall into the range of full siblings (1613-3488), with or without endogamy. This may be, but is not always, especially pronounced in endogamous groups.

As another resource, I wrote an earlier article, Full or Half Siblings, here, that includes some different examples.

Strategy

You have a lot of quills in your quiver now, and I wish you the best if you’re trying to unravel a siblingship mystery.

You may not know who your biological family is, or maybe your sibling doesn’t know who their family is, but perhaps your close relatives know who their family is and can help. Remember, the situation that has revealed itself may be a shock to everyone involved.

Above all, be kind and take things slow. If your unexpected sibling match becomes frightened or overwhelmed, they may simply check out and either delete their DNA results altogether or block you. They may have that reaction before you have a chance to do anything.

Because of that possibility, I recommend performing your analysis quickly, along with taking relevant screenshots before reaching out so you will at least have that much information to work with, just in case things go belly up.

When you’re ready to make contact, I suggest beginning by sending a friendly, short, message saying that you’ve noticed that you have a close match (don’t say sibling) and asking what they know about their family genealogy – maybe ask who their grandparents are or if they have family living in the area where you live. I recommend including a little bit of information about yourself, such as where you were born and are from.

I also refrain from using the word adoption (or similar) in the beginning or giving too much detailed information, because it sometimes frightens people, especially if they know or discover that there’s a painful or embarrassing family situation.

And, please, never, ever assume the worst of anyone or their motives. They may be sitting at their keyboard with the same shocked look on their face as you – especially if they have, or had, no idea. They may need space and time to reach a place of acceptance. There’s just nothing more emotionally boat-capsizing in your life than discovering intimate and personal details about your parents, one or both, especially if that discovery is disappointing and image-altering.

Or, conversely, your sibling may have been hoping and waiting just for you!

Take a deep breath and let me know how it goes!

Please feel free to share this article with anyone who could benefit.

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In Search of…Vendor Features, Strengths, and Testing Strategies

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

In this article, we are going to discuss your goals and why testing or uploading to multiple vendors is advantageous – even if you could potentially solve the initial mystery at one vendor. Of course, the vendor you test with first might not be the vendor where the mystery will be solved, and data from multiple vendors might just be the combination you need.

Testing Strategy – You Might Get Lucky

I recommended in the first article that you go ahead and test at the different vendors.

Some people asked why, and specifically, why you wouldn’t just test at one vendor with the largest database first, then proceed to the others if you needed to.

That’s a great question, and I want to discuss the pros and cons in this article more specifically.

Clearly, that is one strategy, but the approach you select might differ based on a variety of considerations:

  • You may only be interested in obtaining the name of the person you are seeking – or – you may be interested in finding out as much as possible.
  • You may find that your best match at one company is decidedly unhelpful, and may even block you or your efforts, while someone elsewhere may be exactly the opposite.
  • Solving your mystery may be difficult and painful at one vendor, but the answer may be infinitely easier at a different vendor where the answer may literally be waiting.
  • There may not be enough, or the right information, or matches, at any one vendor, but the puzzle may be solvable by combining information from multiple vendors and tests. Every little bit helps.
  • You may have a sense of urgency, especially if you hope to meet the person and you’re searching for parents, siblings or grandparents who may be aging.
  • You may be cost-sensitive and cannot afford more than one test at a time. Fortunately, our upload strategy helps with that too. Also, watch for vendor sales or bundles.

From the time you order your DNA test, it will be about 6-8 weeks, give or take a week or two in either direction, before you receive results.

When those results arrive, you might get lucky, and the answer you seek is immediately evident with no additional work and just waiting for you at the first testing company.

If that’s the case, you got lucky and hit the jackpot. If you’re searching for both parents, that means you still have one parent to go.

Unidentified grandparents can be a little more difficult, because there are four of them to sort between.

If you discover a sibling or half-sibling, you still need to figure out who your common parent is. Sometimes X, Y, and mitochondrial DNA provides an immediate answer and is invaluable in these situations.

It’s more likely that you’ll find a group of somewhat more distant relatives. You may be able to figure out who your common grandparents or great-grandparents are, but not your parent(s) initially. Often, the closer generation or two is actually the most difficult because you’re dealing with contemporary records which are not publicly available, fewer descendants, and the topic may be very uncomfortable for some people. It’s also complicated because you’re often not dealing with “full” relationships, but “half,” as in half-sibling, half-niece, half-1C, etc.

You may spend a substantial amount of time trying to solve this puzzle at the first vendor before ordering your next test.

That second test will also take about 6-8 weeks, give or take. I recommend that you order the first two autosomal tests, now.

Order Your First Two Autosomal Tests

The two testing companies with the largest autosomal databases for comparison, Ancestry, and 23andMe, DO NOT accept DNA file uploads from other companies, so you’ll need to test with each individually.

Fortunately, you CAN transfer your autosomal DNA tests to both MyHeritage and FamilyTreeDNA, for free.

You will have different matches at each company. Some people will be far more responsive and helpful than others.

I recommend that you go ahead and order both the Ancestry and 23andMe tests initially, then upload the first one that comes back with results to both FamilyTreeDNA and MyHeritage. Complete, step-by-step download/upload instructions can be found here.

You can also upload your DNA file to a fifth company, Living DNA, but they are significantly smaller and heavily focused on England and Great Britain. However, if that’s where you’re searching, this might be where you find important matches.

You can also upload to GEDMatch, a popular third-party database, but since you’re going to be in the databases of the four major testing companies, there is little to be gained at GEDMatch in terms of people who have not tested at one of the major companies. Do NOT upload to GEDMatch INSTEAD of testing or uploading to the four major sites, as GEDMatch only has a small fraction of the testers in each of the vendor databases.

What GEDMatch does offer is a chromosome browser – something that Ancestry does NOT offer, along with other clustering tools which you may find useful. I recommend GEDMatch in addition to the others, if needed or desired.

Ordering Y and Mitochondrial DNA Tests

We reviewed the basics of the different kinds of DNA, here.

Some people have asked why, if autosomal DNA shows relatives on all of your lines, would one would want to order specific tests that focus on just one line?

It just so happens that the two lines that Y and mitochondrial DNA test ARE the two lines you’re seeking – direct maternal – your mother (and her mother), and direct paternal, your father (and his father.)

These two tests are different kinds of DNA tests, testing a different type of DNA, and provide very focused information, and matches, not available from autosomal DNA tests.

For men, Y DNA can reveal your father’s surname, which can be an invaluable clue in narrowing paternal candidates. Knowing that my brother’s Y DNA matched several men with the surname of Priest made me jump for joy when he matched a woman of that same last name at another vendor.

Here’s a quote from one of the members of a Y DNA project where I’m the volunteer administrator:

“Thank you for your help understanding and using all 4 kinds of my DNA results. By piecing the parts together, I identified my father. Specifically, without Y DNA testing, and the Big Y test, I would not have figured out my parental connection, and then that my paternal line had been assigned to the wrong family. STR testing gave me the correct surname, but the Big Y test showed me exactly where I fit, and disproved that other line. I’m now in touch with my father, and we both know who our relatives are – two things that would have never happened otherwise.”

If you fall into the category of, “I want to know everything I can now,” then order both Y and mitochondrial DNA tests initially, along with those two autosomal tests.

You will need to order Y (males only) and mitochondrial DNA tests separately from the autosomal Family Finder test, although you should order on the same account as your Family Finder test at FamilyTreeDNA.

If you take the Family Finder autosomal test at FamilyTreeDNA or upload your autosomal results from another vendor, you can simply select to add the Y and mitochondrial DNA tests to your account, and they will send you a swab kit.

Conversely, you can order either a Y or mitochondrial DNA test, and then add a Family Finder or upload a DNA file if you’ve already taken an autosomal DNA test to that account too. Note – these might not be current prices – check here for sales.

You will want all 3 of your tests on the same account so that you can use the Advanced Matches feature.

Using Advanced Matches, you’ll be able to view people who match you on combinations of multiple kinds of tests.

For example, if you’re a male, you can see if your Y DNA matches also match you on the Family Finder autosomal test, and if so, how closely?

Here’s an example.

In this case, I requested matches to men with 111 markers who also match the tester on the Family Finder test. I discovered both a father and a full sibling, plus a few more distant matches. There were ten total combined matches to work with, but I’ve only shown five for illustration purposes.

This information is worth its weight in gold.

Is the Big Y Test Worth It?

People ask if the Big Y test is really worth the extra money.

The answer is, “it depends.”

If all you’re looking for are matching surnames, then the answer is probably no. A 37 or 111 marker test will probably suffice. Eventually, you’ll probably want to do the Big Y, though.

If you’re looking for exact placement on the tree, with an estimated distance to other men who have taken that test, then the answer is, “absolutely.” I wish the Big Y test had been available back when I was hunting for my brother’s biological family.

The Big Y test provides a VERY specific haplogroup and places you very accurately in your location on the Y DNA tree, along with other men of your line, assuming they have tested. You may find the surname, as well as being placed within a generation or a few of current in that family line.

Additionally, the Discover page provides estimates of how far in the past you share a common ancestor with other people that share the same haplogroup. This can be a HUGE boon to a male trying to figure out his surname line and how closely in time he’s related to his matches.

Big Y NPE Examples

Y DNA SNP mutations tested with the Big Y test accrue a mutation about every generation, or so. Sometimes we see mutations in every generation.

Here’s an example from my Campbell line. Haplogroups are listed in the top three rows.

I created this spreadsheet, but FamilyTreeDNA provides a block tree for Big Y testers. I’ve added the genealogy of the testers, with the various Big Y testers at the bottom and common ancestors above, in bold.

We have two red NPE lines showing. The MacFarlane tester matches M. Campbell VERY closely, and two Clark males match W. Campbell and other Campbells quite closely. We utilized autosomal plus the Y results to determine where the unknown parentage events occurred. Today, if you’re a Clark or MacFarlane male, or a male by any other surname who was fathered by a Y chromosome Campbell male (by any surname), you’ll know exactly where you fit in this group of testers on your direct paternal line.

Y DNA is important because men often match other men with the same surname, which is a HUGE clue, especially in combination with autosomal DNA results. I say “often,” because it’s possible that no one in your line has tested, or that your father’s surname is not his biological surname either.

Y and mitochondrial DNA matches can be HUGELY beneficial pieces of information either by confirming a close autosomal relationship on that line, or eliminating the possibility.

Lineage-Specific Population Information

In addition to matching other people, both Y and mitochondrial DNA tests provide you with lineage-specific population or “ethnicity” information for this specific line which helps you focus your research.

For example, if you view the Y DNA Haplogroup Origins shown for this tester, you’ll discover that these matches are Jewish.

The tester might not be Jewish on any other genealogical line, but they definitely have Jewish ancestry on their Y DNA, paternal, line.

The same holds true for mitochondrial DNA as well. The main difference with mitochondrial DNA is that the surname changes with each generation, haplogroups today (pre-Million Mito) are less specific, and fewer people have been tested.

Y and Mitochondrial DNA Benefits

Knowing your Y and mitochondrial DNA haplogroups not only arm you with information about yourself, they provide you with matching tools and an avenue to include or exclude people as your direct line paternal or maternal ancestors.

Your Y and mitochondrial DNA can also provide CRITICALLY IMPORTANT information about whether that direct line ancestor belonged to an endogamous population, and where they came from.

For example, both Jewish and Native populations are endogamous populations, meaning highly intermarried for many generations into the past.

Knowing that helps you adjust your autosomal relationship analysis.

Why Order Multiple Tests Initially Instead of Waiting?

If you’ve been adding elapsed time, two autosomal tests (Ancestry and 23andMe), two uploads (to FamilyTreeDNA and MyHeritage,) a Y DNA test, and a mitochondrial DNA test, if all purchased serially, one following the other, means you’ll be waiting approximately 6-8 months.

Do you want to wait 6-8 months for all of your results? Can you afford to?

Part of this answer has to do with what, exactly, you’re seeking, and how patient you are.

Only you can answer that question.

A Name or Information?

Are you seeking the name or identity of a person, or are you seeking information about that person?

Most people don’t just want to put a name to the person they are seeking – they want to learn about them and the rest of the family that door opens.

You will have different matches at each company. Even after you identify the person you seek, the people you match may have trees you can view, with family photos and other important information. (Remember, you can’t see living people in trees.) Your matches may have first-person information about your relative and may know them if they are living, or have known them.

Furthermore, you may have the opportunity to meet that person. Time delayed may not be able to be recovered or regained.

One cousin that I assisted discovered that his father had died just six weeks before he broke through that wall and made the connection.

Working with data from all vendors simultaneously will allow you to combine that data and utilize it together. Using your “best” matches at each company, augmented by X, Y, and/or mitochondrial DNA, can make MUCH shorter work of this search.

Your closest autosomal matches are the most important and insightful. In this series, I will be working with the top 15 autosomal results at each vendor, at least initially. This approach provides me with the best chance of meaningful close relationship discoveries.

Data and Vendor Results Integration

Here’s a table of my two closest maternal and paternal matches at the four major vendors. I can assign these to maternal or paternal sides, because I know the identity of my parents, and I know some of these people. If an adoptee was doing this, the top 4 could all be from one parent, which is why we work with the top 15 or so matches.

Vendor Closest Maternal Closest Paternal Comments
Ancestry 1C, 1C1R Half-1C, 2C I recognized both of the maternal and neither of the paternal.
23andMe 2C, 2C 1C1R, half-gr-niece Recognized both maternal, one paternal
MyHeritage Mother uploaded, 1C Half-niece, half-1C Recognized both maternal, one paternal
FamilyTreeDNA Mother tested, 1C1R Parent/child, half-gr-niece uploaded Recognized all 4

To be clear, I tested my mother’s mitochondrial DNA before she passed away, but because FamilyTreeDNA archives DNA samples for 25 years, as the owner/manager of her DNA kit, I was able to order the Family Finder test after she had passed away. Her tests are invaluable today.

Then, years later, I uploaded her results to MyHeritage.

If I was an adopted child searching for my mother, I would find her results in both databases today. She’ll never be at either 23andMe or Ancestry because she passed away before she could test there and they don’t accept uploads.

Looking at the other vendors, my half-niece at MyHeritage is my paternal half-sibling’s daughter. My half-sibling is deceased, so this is as close as I’ll ever get to matching her.

At 23andMe, the half-great-niece is my half-siblings grandchild.

It’s interesting that I have no matches to descendants of my other half-sibling, who is also deceased. Maybe I should ask if any of his children or grandchildren have tested. Hmmmm…..

You can see that I stand a MUCH BETTER chance of figuring out close relatives using the combined closest matches of all four databases instead of the top matches from just one database. It doesn’t matter if the database is large if the right person or people didn’t test there.

Combine Resources

I’ll be providing analysis methodologies for working with results from all of the vendors together, just in case your answer is not immediately obvious. Taking multiple DNA tests facilitates using all of these tools immediately, not months later. Solving the puzzle sooner means you may not miss valuable opportunities.

You may also discover that the door slams shut with some people, or they may not respond to your queries, but another match may be unbelievably helpful. Don’t limit your possibilities.

Let’s take a look at the strengths of each vendor.

Vendor Strengths and Things to Know

Every vendor has product strengths and idiosyncracies that the others do not. All vendors provide matches and shared matches. Each vendor provides ethnicity tools which certainly can be useful, but the features differ and will be covered elsewhere.

  • AncestryAncestry has the largest autosomal database and includes ThruLines, but no Y or mitochondrial DNA testing, no clusters, no chromosome browser, no triangulation, and no X chromosome matching or reporting. Ancestry provides genealogical records, advanced tools, and full tree access to your matches’ trees with an Ancestry subscription. Ancestry does not allow downloading your match list or segment match information, but the other vendors do.
  • 23andMe 23andMe has the second largest database. They provide triangulation and genetic trees that include your closest matches. Many people test at 23andMe for health and wellness information, so 23andMe has people in their database who are not specifically interested in genealogy and probably won’t have tested elsewhere, but may be invaluable to your search. 23andMe provides Y and mtDNA high-level haplogroups only, but no matching or other haplogroup information. If you purchase a new test or have a V5 ancestry+health current test, you can expand your matches from a limit of 1500 to about 5000 with an annual membership. For seeking close relatives, you don’t need those features, but you may want them for genealogy. 23andMe is the only vendor that limits their customers’ matches.
  • MyHeritageMyHeritage has the third largest database that includes lots of European testers. MyHeritage provides triangulation, Theories of Family Relativity, and an integrated cluster tool* but does not report X matches and does not offer Y or mitochondrial DNA testing. MyHeritage accepts autosomal DNA file uploads from other testing companies for free and provides access to advanced DNA features for a one-time unlock fee. MyHeritage includes genealogical records and full feature access to advanced DNA tools with a Complete Subscription. (Free 15 days trial subscription, here.)
  • FamilyTreeDNA Family Finder (autosomal)FamilyTreeDNA is the oldest DNA testing company, meaning their database includes people who initially tested 20+ years ago and have since passed away. This, in essence, gets you one generation further back in time, with the possibility of stronger matches. Their Family Matching feature buckets and triangulates your matches, assigning them to your maternal or paternal sides if you link known matches to their proper place in your tree, even if your parents have not tested. FamilyTreeDNA accepts uploads from other testing companies for free and provides advanced DNA features for a one time unlock fee.
  • FamilyTreeDNAFamilyTreeDNA is the only company that offers both Y and mitochondrial DNA testing products that include matching, integration with autosomal test results, and other tools. These two tests are lineage-specific and don’t have to be sorted from your other ancestral lines.

I wrote about using Y DNA results, here.

I wrote about using mitochondrial DNA results, here.

*Third parties such as Genetic Affairs provide clustering tools for both 23andMe and FamilyTreeDNA. Clustering is integrated at MyHeritage. Ancestry does not provide a tool for nor allow third-party clustering. If the answer you seek isn’t immediately evident, Genetic Affairs clustering tools group people together who are related to each other, and you, and create both genetic and genealogical trees based on shared matches. You can read more about their tools, here.

Fish in all the Ponds and Use All the Bait Possible

Here’s the testing and upload strategy I recommend, based on the above discussion and considerations. The bottom line is this – if you want as much information as possible, as quickly as possible, order the four tests in red initially. Then transfer the first autosomal test results you receive to the two companies identified in blue. Optionally, GEDMatch may have tools you want to work with, but they aren’t a testing company.

What When Ancestry 23andMe MyHeritage FamilyTreeDNA
Order autosomal Initially X X    
Order Y 111 or Big-Y DNA test if male Initially       X
Order mitochondrial DNA test Initially if desired       X
Upload free autosomal When Ancestry or 23andMe results are available     X X
Unlock Advanced Tools When you upload     $29 $19
Optional GEDMatch free upload If desired, can subscribe for advanced tools

When you upload an autosomal DNA file to a vendor site, only upload one file per site, per tester. Otherwise, multiple tests simply glom up everyone’s match list with multiple matches to the same person.

Multiple vendor sites will hopefully provide multiple close matches, which increase your opportunity to discover INFORMATION about your family, not just the identity of the person you seek.

Or maybe you prefer to wait and order these DNA tests serially, waiting until one set of results is back and you’re finished working with them before ordering the next one. If so, that means you’re a MUCH more patient person than me. 😊

Our next article in this series will be about endogamy, how to know if it applies to you, and what that means to your search.

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Ancestry Only Shows Shared Matches of 20 cM and Greater – What That Means & Why It Matters

Recently, I’ve noticed an uptick in confused people who’ve taken Ancestry’s DNA test.

They are using shared matches, which is a great tool and exactly what they should be doing, but they become confused when no shared matches appear with some specific people.

This is especially perplexing when they know through information sharing or because they manage multiple DNA kits that those two people who both match them actually do share DNA and match each other, meaning they “should” appear on a shared match list. Or worse, yet, conflicting match information is displayed, with one person showing the shared match, but the other person reciprocally does not.

What gives?

That’s exactly what this article addresses. It’s not quite as simple as it sounds, but it’s certainly easier once you understand.

What Are Matches and Shared Matches?

Matches occur when two people match each other. From your perspective as a DNA tester, matches are people who have taken DNA tests and appear on your match list because you share some level of DNA equal to or greater than the match threshold of the vendor in question.

At Ancestry, that minimum matching threshold is 8 cM (centimorgans) of matching DNA.

Individual matches are always one-to-one. Your match list is a list of people who all match you.

So, you match person 1, and you match person 2, individually.

Your matches may or may not also match each other. If they do match each other in addition to matching you, that’s a shared match which is a hint as to a potential common ancestor between all three people.

Shared matches are a list of people who match you PLUS any one other match on your list. In other words, shared matches are three-way matches.

In the diagram above, you can see that you match Match 1 and you also match Match 2. In this case, Match 1 and Match 2 also match each other, so all three of you match each other, but not necessarily on the same segment. Therefore, you’re all three shared matches, as shown in the center of the three circles.

Viewing Shared Matches

To view a list of people who match you and Match 1, you would request shared matches with Match 1 by clicking on “View Match” or “Learn More” on your match list, then on “Shared Matches” on the next screen.

The resulting shared match list consist of people who match you AND Match 1, both. It’s easy to make assumptions about why you have shared matches, but don’t.

Shared Matches are Hints

A shared match CAN mean:

  • That all three people share a common ancestral line.
  • You share a common ancestor with Match 1 and Match 2, but Match 1 and 2 match each other because they share an entirely different ancestor.
  • You match Match 1 because you share DNA from Ancestor A and you match Match 2 because you share DNA from Ancestor B. Match 1 and 2 match each other either because they share one or both of those common ancestors.
  • Match 1 and Match 2 might match because Match 1 and Match 2 share an ancestor that isn’t related to you.
  • That one (or more) of the matches is identical by chance, meaning the DNA combined from two parents in a random way that just happens to match with someone else.

Shared matches are great hints to be sifted for relevance. The operative word here is hint.

What If We Don’t Have Shared Matches?

Conversely, NOT having a shared match doesn’t mean you don’t share a common ancestor.

Sorry about the triple negative. Let me say that another way, because this is important.

Even though you and someone else aren’t on a shared match list, you might still share DNA and you may share a common ancestor, whether you share their DNA or not.

Ancestry’s shared matches work differently than shared matches at other vendors. Before we discuss that, let’s talk about why shared matches are important.

Why Do Shared Matches Matter Anyway?

Matches and shared matches are how genealogists perform two critically important functions:

  • Verifying “known” ancestors. Sometimes paper trails aren’t accurate and certainly, neither are trees.
  • Identifying unknown ancestors. Looking for common families among shared DNA matches is a HUGE hint when tracking down those pesky unknown ancestors.

I wrote about shared matches, here, when Ancestry purged segments under 8 cM, but I think the message about the limitations of shared matches and how the process actually works deserves its own article, especially for new users. Shared matches and segment cM numbers can be quite confusing, but they don’t need to be.

I wrote an article titled DNA Beginnings: Matching at Ancestry and What It Means that includes lots of useful information.

Ok, now let’s look specifically at using shared matches and why sometimes shared matches just don’t seem to make sense.

Matches

By far, the majority of your matches at any vendor will be more distant matches. That’s because you have thousands of distant relatives, most of whom you don’t know (yet).

You’ll only have a few closer relatives.

At Ancestry, I have 102,000+ total matches, of which more than 97,000 are distant matches. Based on these numbers, keep in mind that about 95.74% of my matches are distant, meaning 20 cM or below, and yours probably are too. You’ll need that number later.

Note that 20 cM is Ancestry’s threshold between close matches and distant matches.

That’s about exactly where you’d expect, on average, to see a 20 cM match – generally at or further back than 4th cousins. 20 cM is roughly the 4th to 6th cousin level.

Of course, you won’t match most of your 5th cousins at all, yet you’ll match some with more than 20 cM. That’s just the roll of the genetic dice.

Closer ancestors (meaning closer matches) is also the area of genealogy where much of the lower-hanging fruit has been plucked.

In my case, the closest unknown ancestor in my tree occurs at the 6th generation level and I have 5 or 6 missing sixth-generation ancestors – all females with no surnames. Two have no names at all.

Click to enlarge any image

How Much DNA Do Cousins Share?

One of my priorities as a genealogist is to identify those unknown people, which is why matches, and shared matching at that level are critical for me.

Ancestry tells me that this 20 cM match is likely my 4th-6th cousin.

At DNAPainter, in the Shared cM Tool, you can enter the total cM number of a match, which is the total amount of DNA that you share after Ancestry’s Timber algorithm has been applied. The range of relationship probabilities for 20 cM is shown below.

For a total match of 20 cM with another individual, several relationships ranging between half 3C2R/3C3R and 8th cousins are the most probable relationships at 58%.

For the record, this is total cM, which does not necessarily mean one segment. Ancestry reports the number of segments, but Ancestry does not show you the segment locations, nor do they have a chromosome browser. Without a chromosome browser, you have no way of determining whether or not you match with shared matches on the same segment(s). In other words, there is no triangulation at Ancestry, meaning confirmation of a specific shared DNA segment descended from a common ancestor. You can find triangulation resources, here.

Close Matches

The best way to figure out how you are related to closer matches (assuming you don’t already know them and Ancestry has not found a common ancestor) is using shared matches. Hopefully, you will share matches with people you do know or with whom you’ve already identified your common ancestor.

One of my relatively close DNA matches at Ancestry is Lonnie. I don’t know Lonnie, but it looks like I should because he’s probably a 1st or 2nd cousin. We share 357 cM of DNA over 20 segments.

I thought I knew all of my 1st and 2nd cousins. Let’s see if I can figure out how I’m related to Lonnie.

By clicking on Lonnie’s name on my match list, then on Shared Matches, I can determine that Lonnie and I connect through my Estes and Vannoy lines based on who we both match, which means that our common ancestor is either my paternal grandfather or my great-grandparents, Lazarus Estes and Elizabeth Vannoy.

You can see the notes I’ve made about these matches I share with Lonnie.

Viewing Lonnie’s unlinked tree verifies the ancestral line that shared matches suggest. An unlinked tree means that Lonnie has not linked his DNA test to himself in his tree. Since Ancestry doesn’t know who he is in the tree, they can’t find a common ancestor for me and Lonnie. However, I can by viewing his tree.

Our common ancestor is Lazarus Estes and his wife, Elizabeth Vannoy. Therefore, Lonnie is my 2nd cousin.

That wasn’t difficult, in part because I had already worked on the genealogy of our common matches and Lonnie had a small unlinked tree where I could confirm our common ancestor.

Now let’s move to more distant, not-so-easy matches.

Distant Matches

I’ve spent a lot of time over the years identifying common ancestors with my matches.

When I make that connection, whether or not Ancestry has been able to identify our common ancestor, I make notes about common ancestors and anything else that seems relevant. Notes very conveniently show on my match list so I don’t need to open each match to see how we are related.

Ancestry does identify potential common ancestors using ThruLines. Note the word potential. Ancestry compares the trees of you and your matches searching for common ancestors and suggests connections. It’s up to you to verify. ThruLines are hints, not gospel. Additionally, you may have multiple ancestral links to your matches. Ancestry can only work with the fact that you have a DNA match with someone AND the user-provided trees of your matches.

Ancestry’s ThruLines only reach back a maximum of 7 generations to suggest common ancestors. At 7 generations distance, you’d be a 5th cousin to a descendant who is also 7 generations downstream from that ancestor.

The information from DNAPainter, who utilizes the Shared CM Project compiled data shows that the most likely amount of shared DNA for 5th cousins, is, you’ve guessed it – 20 cM.

Jacob Dobkins is my 7th generation ancestor. I have ThruLines for him and his wife, but not for their parents who are one generation too distant for ThruLines. I’d LOVE to see Ancestry extend ThruLines another 2 or 3 generations.

ThruLines matches me with people who descend from Jacob through his other children. Other children are important because the only ancestors you share with those people are (presumably) that ancestral couple.

Matches with Jacob’s descendants range from 8 cM (the smallest amount Ancestry reports) to 32 cM.

Here’s an example.

Ancestry displays some shared matches with all of your matches, regardless of the size of your match to that person. However, Ancestry ONLY shows shared matches to a third person if you share more than 20 cM of DNA with that third person.

For example, I match KO with 8 cM of DNA. Ancestry shows my shared matches with KO, below.

I only have 3 shared matches with KO. I only match KO at 8 cM, but I match our shared matches at 39, 31 and 21 cM, respectively.

Ancestry does NOT show shared matches below 20 cM, so it’s unknown how many additional shared matches KO and I actually have if shared matches less than 20 cM were displayed.

Perspective is Critical

Whether you see a shared match or not is sometimes a matter of perspective, meaning which of two people you request shared matches with.

In this case, I requested shared matches with KO. I only share 8 cM of DNA with KO, but that doesn’t matter. The amount of DNA you share with the person you’re requesting shared matches with is irrelevant.

Ancestry’s Shared Matches with KO include Ker

I will see shared matches with KO to anyone we mutually share as matches above 20 cM, including Ker.

If I request shared matches with Ker, with whom I share 39 cM of DNA, I will see all of our mutual matches at 20 cM (or greater) of DNA. However, that does NOT include KO because I only share 8 cM of DNA with KO.

This restriction applies regardless of how much DNA KO and Ker share, which is an unknown to me of course.

Ancestry’s Shared Matches with Ker does NOT include KO

Nothing has changed between these matches, yet KO does not appear on my shared matches list with Ker when I request shared matches with Ker.

I still share 8 cM with KO and 39 cM with Ker. KO and Ker still both match each other. The only difference is that Ker shows up on my shared match list with KO because I share more than 20 cM with Ker. However, when I request a match list with Ker, KO does NOT appear because I only share 8 cM with KO.

This is the source of the confusion and often, why people disagree about shared matches. It’s kind of a “now you see it, now you don’t” situation.

If a person shows as a shared match depends on:

  1. Whether the third person actually does share DNA with the tester and the person they’ve asked for shared matches with
  2. Whether the third person shares 20 cM DNA or more with the tester, the person requesting the shared match list with one of their matches

Whether someone appears on a shared match list can literally be a matter of perspective unless the match and the shared matches all match the tester at 20 cM or larger.

Another Example

Let’s look at a larger match to a descendant of the same ancestor.

I share exactly 20 cM with Joyce, my 5C1R.

Viewing my shared matches with Joyce, I match 50 other people that she matches as well.

I only share 25 cM of DNA with the smallest match with Joyce. Apparently, there are no matches with Joyce with whom I share between 20 and 25 cM of DNA.

Bottom Line

Here’s the bottom line.

Ancestry NEVER shows any shared matches below 20 cM from the perspective of the tester, meaning people who match you and someone else, both.

If you recall our earlier math, that means that approximately 95.74% of my shared matches aren’t shown.

This puts shared matches in a different perspective because now I realize just how many matches I’m not seeing.

Why is This Confusing?

If you aren’t aware of this shared match limitation, and that a majority of your shared matches are actually below 20 cM, you may interpret shared match results to mean you actually DON’T share specific matches with that other person. That isn’t necessarily true, as we saw above with KO and Ker.

Furthermore, let’s say you manage your DNA kit plus 3 more, A, B and C. Because you manage all 4 kits, that means you can see the results for all 4 people.

  • A – 10 cM
  • B – 20 cM
  • C – 40 cM

From the perspective of YOUR kit, you will see some shared matches FOR all of those matches.

What you won’t see is shared matches if you don’t match the shared match (third person) at 20 cM or greater.

Always remember, shared match information at Ancestry is ALWAYS from the perspective of your DNA kit combined with the person with whom you request the match.

I’ve put this information in a grid because that’s how I make sense of things like this.

Here are your matches. When you click on shared matches with person A who you match at 10 cM, you’ll see both person B and person C as shared matches since you match both of those people at 20 cM or larger. You WILL see 20 cM shared matches, but you will not see 19 cM shared matches.

When you request shared matches for A, you will see both B and C.

When you request shared matches with kits B and C, you will not see A because you only match them at 10 cM.

However, from the perspective of DNA kits A, B and C, shared matches look different.

Let’s look at shared matches from the perspective of Kits A, B and C.

Kit A matches you, Kit B and C, but can only see Kit B as a shared match because matches with you and Kit C are under 20 cM.

Kit B doesn’t match C at all, so they clearly won’t have shared matches. However, they do match you and Kit A, both at 20 cM and over, so Kit B will see you as a shared match with Kit A, and Kit A as a shared match with you.

Kit C doesn’t match Kit B, so no shared matches with that person at all. Kit C does match you and Kit A. However, when Kit C clicks on shared matches for you, Kit A doesn’t show up because they only match Kit A on 9 cM. When Kit C clicks on Kit A for shared matches, you ARE listed as a shared match because you share 40 cM of DNA with Kit C.

There’s no way to discern whether two of your matches match each other unless they show as a match in the shared match tool. You can’t tell if their absence on the shared match list means they actually don’t match, or their shared match absence is because they match you at less than 20 cM.

Whew, that was a mouthful.

You may need to refer back to this from time to time if you’re confused by your shared matches at Ancestry.

If you need to remember rules, remember this.

  1. You can obtain shared matches with yourself plus any match, regardless of how much or how little DNA you share with that one match. Prove this to yourself by finding a match under 20 cM, like my 8 cM match, and viewing your shared matches.
  2. No one will show on a shared match list with another person unless they match you at 20 cM or greater. Prove this to yourself by viewing the smallest shared match with anyone.

Strategy

The takeaway of this is if you have a larger (20 cM or over) and smaller match (under 20 cM), always request shared matches from the perspective of the smaller match because the smaller match won’t show up as a shared match on any shared match list.

The only way you can see shared matches that includes people under 20 cM is to request to view shared matches with individual people who match you below 20 cM. 

In my case, I will never see KO on any shared match list because I only match KO at 8 cM. However, I can request my shared matches with KO in which case I’ll see all 20 cM or greater shared matches with KO.

Alternatives

Every vendor provides a shared match feature, and each functions differently.

In the chart below, I’ve provided basic shared match information for each vendor.

If you’re interested in uploading your DNA file from Ancestry or another vendor, I’ve provided upload/download step-by-step instructions for each vendor, here.

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