We Match…But Are We Related?

Last week, I received this question from a reader, we’ll call him Jim:

“I match Susie on the HVR1 and HVR2 regions of our mitochondrial DNA….but I was just wondering….are we related?’

Well, the answer is yes…and maybe.

You see, the answer hinges on the definition of the word “related.”

If Jim means related at any point in time, the answer is yes.  If Jim and Susie share the same haplogroup, at any level, then they did indeed share an ancestor at some point in the past. The question is – how long ago?  And that part of the answer isn’t easy.

Now, if what Jim means is related in the sense of “in a genealogically meaningful timeframe,” which is generally anytime from the present back in time roughly 500 or maybe as long as 800 years….the answer is a resounding maybe.

And of course, the answer differs a bit, depending on whether you’re talking about mitochondrial DNA, Y DNA or autosomal DNA.

Let’s look at all 3 types of DNA tests.

Mitochondrial DNA

First, Jim doesn’t have enough information to make that “genealogically meaningful” determination. To do that, he and his match both need to test at the full sequence level for mitochondrial DNA.  The full sequence test tests all 16,569 locations of the mitochondria, where the HVR1+HVR2 tests only 1135 locations.  Family Tree DNA is the only testing company to provide this level of testing.

Jim needs more information.

If Jim and Susie match at the full sequence level too, then the genealogical timeframe becomes possible. If they match with no mutations, meaning a genetic distance of zero, it becomes even more likely, but it’s certainly not a given – nor is figuring out who the common ancestor might be.  For example, below are my closest full sequence matches and my most distant matrilineal ancestor was from Germany.  Most of these matches are Scandinavian.

match mito

However, exact full sequence matches are where you start to look for a common ancestor. No common ancestor found?  Then at least look for common geography.

One of the easiest ways to do that, for both mitochondrial DNA and Y DNA, at Family Tree DNA, is by utilizing the Matches Map, available on your toolbar.

match matches map'

Assuming your matches have completed their most distant ancestor’s location (which is not always the case,) it’s easy to look for match groups and clusters on the map. Your most distant ancestor’s balloon will be white, with your matches color coded.  You can click on any of the balloons to see the match, their ancestor and location.  These are my full sequence matches.  Surprisingly, my closest matches aren’t in Germany at all!!!  Hmmm….time to start looking at what happened in history that might account for this population movement.

In many cases, people will match at the HVR1 and HVR2 levels, but not match at higher levels. In fact, they may both be haplogroup H (for example) at the HVR1 and HVR2 levels, but the full sequence testing refines their haplogroups and their extended haplogroups may no longer match each other.  For example Jim’s refined haplogroup could be H2 and Susie’s ’s H6.  Both are subgroups of H, who was born roughly 12,800 years ago, according to “A ‘Copernican’ Reassessment of the Human Mitochondrial DNA Tree from its Root” by Behar et al, published in The American Journal of Human Genetics 90, 675–684, April 6, 2012.

So, yes, Jim and Susie are definitely related in the past 12,000 years – but I’m not thinking this is what Jim was really asking. I refer to this as “haplogroup cousins.”

However, a lot has happened in 12,000 years. As in, mutations happened, and subgroups emerged.  So while Jim and Susie might both be members of haplogroup H, they are not both members of the same subgroup, so their ancestors both developed mutations which classify them into subgroups H2, born not long after H was born, and H6, born about 11,000 years ago.

So, the bottom line is if you don’t match at the full sequence level, you’re not related in a genealogically meaningful time frame. If you do match at the full sequence level, you might be related in a genealogically meaningful timeframe.

A couple years ago, I set about looking at mitochondrial DNA mutation rates and discovered that the only academic paper published that addressed this in the HVR1, HVR2 and coding regions was written about penguins. Not exactly what I was looking for, but it does explain why there is no TIP type calculator for mitochondrial DNA.

Family Tree DNA does provide some guidelines in their learning center.

    • Matching at the HVR1 level means that you have a 50% chance of sharing a common maternal ancestor within the last fifty-two generations. That is about 1,300 years.
    • Matching on HVR1 and HVR2 means that you have a 50% chance of sharing a common maternal ancestor within the last twenty-eight generations. That is about 700 years.
    • Matching exactly on the Mitochondrial DNA Full Sequence test brings your matches into more recent times. It means that you have a 50% chance of sharing a common maternal ancestor within the last 5 generations. That is about 125 years.

I personally think that the 5 generation estimate of a 100% match for the full sequence is overly optimistic. In fact, a lot overly optimistic.  I do find people who do share common ancestors at the full sequence level, but it’s the exception and not the rule – although part of that may be because the surname changes every generation so it’s genealogically difficult to track.  However, genealogical matches would be much more common if more people tested their mitochondrial DNA.

You can see a good example in this article of how mitochondrial DNA told me a story I didn’t know about my matrilineal line – and would never have known without full sequence testing.

What I didn’t include in this article is that many of my mitochondrial DNA matches shared their mutation information with me, and I created a “tree” that showed exactly where each mutation happened and who shared a common ancestor with whom.

I obviously can’t share that chart publicly, but the chart below conveys the methodology. The oldest known ancestors of these matches lived in the locations listed at the bottom of the chart.

match 1

In the above case, you can clearly see that it’s very likely that the founder lived in Scandinavia because at least some of the descendants of all three unique mutation groups, A, B and C live in Scandinavia today. However, Mutation J is found in Germany.  This suggests that sometime after the common mutation, F, an individual migrated from Scandinavia to Germany.  Mutation K, who also shares mutation F, is still in Scandinavia today.

Y DNA

It’s a bit easier to answer the “are we related” question for Y DNA because the surnames are often the same. So yes, if you match on STR markers (those are panels for 12, 25, 37, 67 and 111 markers) and you carry the same surname, you’re likely related in a genealogically relevant timeframe.  Don’t you hate it when you see those weasel words like “likely?”

However, if your surname is Smith, or something else very common, and you only match at 12 markers, and you don’t match at higher levels, then again, you’re probably a haplogroup cousin. Names like Smith and Miller are occupation names and every village across continental Europe had at least one at all times.  So, there are lots of Smiths and Millers that have the same base haplogroup and aren’t related in a genealogically meaningful timeframe.

You can see an example of this in my Miller-Brethren project. These are Miller families, German in origin, who belonged to the small German Brethren religious group.

Match Miller 1

Match Miller 2

I thought this would be a relatively small, easy project, but not so much. There were a lot more genetically different Miller surname groups even within the small Brethren church than I expected.

As you can see, many of these groups share haplogroups, especially major haplogroups like R-M269.

In some groups, some individuals have tested additional SNPs by taking either individual SNP tests, the Big Y or SNP panel tests, offered on their individual pages.

So, for example, you may see the haplogroup designations of R-M269 and R-CTS7822 in the same family grouping where the STR markers match exactly or nearly. Confusing?  Yes, but that means that one individual had taken additional testing.  If you look at the haplogroup trees, you would see that CTS7822 is downstream of M269 in haplogroup R.

The important thing for finding genealogically relevant matches is matching high numbers of STR markers. I encourage everyone to test at 67 markers, and I like to see 111 if the budget allows.

If you match someone at 67 markers, exactly, there’s a very good chance you’re very closely related.

For example, cousin Rex matches cousin Richard at 67 markers with only 3 differences. I happen to have their genealogy, and I know when these two men’s lines diverge.  They descend from two different sons of Michael Miller (Mueller) who was born in 1692.  Three cumulative Y STR mutations have happened since that time in these men’s two lines.

Match Miller 3

Rex’s haplogroup is R-M269, but Richard took the Big Y test, so his haplogroup is shown as R-CTS7822 and he now sits as proxy for the rest of the Michael Miller descendant group.

Y matches have access to the TIP calculator, that little orange box shown on the match page above to the right of each matches name.  The TIP calculator provides generational estimates to a common ancestor, weighted by haplogroup marker mutation frequency.

The TIP calculator shows us that, based on their mutations at 67 markers, these two men are most likely to be related between 6 and 7 generations. At the 50th percentile, they are as likely to be related sooner as later, so the 50th percentile is the number I tend to use for an estimate of the distance to the most recent common ancestor.

Match tip

In fact, their common ancestor is 7 generations ago, counting their parents as generation 1.

The more markers tested, the more data you, and the TIP calculator, have to work with. I’ve found the TIP calculator to be quite accurate at 67 and 111 markers when using the 50th percentile as a predictor.

What? You say you don’t match anyone with your surname?

That’s more common than you think.

One of two things could have happened.

First, your paternal surname line may simply have not tested yet.

You may be able to search in the appropriate surname project and find a group of people who descend from “your” ancestor with different DNA. That’s a pretty big hint too, assuming the genealogy is accurate.  If the genealogy is accurate, and your line is the “odd man out,” the next question is always “when did the genetic break occur,” and why.  That leads us to the second scenario.

Second, there could be an undocumented adoption in your line. I’m using undocumented adoption in the most general sense here, meaning anything from a child taking a step father’s name to a true adoption.  The surname does not match the biological line and we don’t know why – so some “adoption” of some sort took place someplace.

The question is, one or two?

I first ask people if they really want to know the answer, because once you pursue this avenue, you can’t close Pandora’s box.

If the answer is yes, they are sure, then I suggest they find a male with their surname that they know should be related and test him.

The answer will become obvious at that point, and the test plan from there forward should reflect the discovery from that test.

Autosomal

The question of “are we related” can be more obtuse when discussing autosomal DNA.

On the other hand, like with Y DNA, the answer can be very evident.

In fact, there is an entire spectrum of autosomal DNA matches and I wrote about how much confidence you should put in each type.

But let’s get down to the very basic brass tacks.

There are only two ways you can match someone’s autosomal DNA.

Either you share a common ancestor or you are matching by chance.

When you receive DNA from your parents, that DNA came from their ancestors as well. All of the DNA you receive from your parents came from some ancestor.

Then, how can you match someone by chance?

You have two strands of autosomal DNA. Think of two lanes of a street.  However, the houses on both sides of that street have the same address.  Your Mom’s DNA value goes in front of one house, in one lane, and your Dad’s goes in front of the house with the same address in the other lane, but we don’t know whose DNA is whose and there is no consistency in whose DNA goes in which lane.

So, it looks like this.

match autosomal strands

You can see in this example that you received As in all positions from Mom and Cs in all positions from Dad. However, these alleles can be positioned in either your strand 1 or 2, so the entire roughly 700,000+ locations typically tested for genealogy is mixed between Mom and Dad.  So, there is no way to tell, just by looking at your DNA, which DNA in any position (strand 1 or 2 at any address) came from whom.

You can also see, looking at the chart above, that if someone matches you on all As, they match you on your Mom’s side, and if they match you on all Cs, they match you on your Dad’s side. This is called identical by descent.  This means, yes, you are related.

But what happens if someone has ACA? They match you too, by zigzagging back and forth between your Mom and Dad’s DNA.  That’s called identical by chance, and it’s not a valid genealogical match. This means, no, you’re not related, at least not on this segment.

I wrote more about this phenomenon and tools to work with your DNA in “One Chromosome, Two Sides, No Zipper.”

How can you tell the difference between identical by descent (related) and identical by chance (not related)? Therein lies the big question.

If you match someone who also matches one of your parents, then you match them through that side of your family – identical by descent from a common ancestor.

Don’t have parents to test?  Then how about your parents siblings, aunts, uncles, first cousins….etc.  Often the best way to tell if a match is a legitimate match is by who else they match that also matches you.  This is why we encourage people to test all of their relatives!

And that, of course, leads to identifying the common ancestor. For example, if you match someone who also matches your first cousin on the same segment, your common ancestor has to be in that same genealogical line shared by you and your first cousin.  This technique is called triangulation.

I wrote more about cousin matching too, in “Just One Cousin.”

You can read more on this general topic here and here, as well.

I wrote a primer for folks just getting autosomal results back called “Autosomal DNA Testing 101 – Now What?”

Combination Tools

There are several ways to match people. Sometimes looking at combinations of tools is quite helpful as well.

One of my favorite and little known methodologies is to combine two tools together.  This is only available at Family Tree DNA, because they are the only vendor who also performs the mitochondrial and Y DNA tests in addition to the autosomal testing.

For example, if you match someone on the Y or mitochondrial DNA, notice if they have taken the Family Finder test as well. If they have, the little icon by their name on your match list will say “FF.”

If so, by using the Advanced Matching tool, available under “Tools and Apps” on your personal page Toolbar at Family Tree DNA, you can query to see who matches you utilizing multiple tools.

match toolbar

For example, for cousin Rex, I wanted to know who he matched on BOTH his Y 12 marker test and the Family Finder test. Sure enough, two individuals match him on both.

match combo

Please note that I could also have performed this same search within any project by utilizing the “show matches for” drop down box.

Summary

I hope this quick broad-brush survey of the various DNA testing tools and what your matches mean for each type has helped you to take some of those matches from the “maybe” to the “yes” or “no” category.

After all, the fun in all of this is to discover as much as we can about our ancestors by who we are related to. Guilt by genetic association.  There is something to be learned from every match or group of matches if we’re listening…even if it is that your German 4Xgreat-grandmother’s lineage was likely originally Scandinavian.  I don’t know about you, but that tidbit of knowledge and the doors it opens was well worth the price of admission, all by itself.

And just think, you’ll never have the opportunity to find out if you’re related if you don’t test and work with your results!  There is so much waiting to be discovered.

14 thoughts on “We Match…But Are We Related?

  1. Very good information. I am a Thompson, an on my YDNA-111 I only match a Hill and a Fletcher. I believe there is an undocumented adoption for my ancestor in 1859, when my Ancestor was born which is also the same year his sister married a Hill, and they were living in the same household in 1860 with her parents. But being so far back it is hard to find any official documentation to prove it.
    But very informative article thank you.

  2. [i][quote]Please note that I could also have performed this same search within any project by utilizing the “show matches for” drop down box.[/quote][/i]

    I think this option is not available to project participants – only administrators. I don’t see it on any of my projects.

    The timeout monster is not letting me see any Y12-FF matches. Come, upgrades, get working! 😀

    • There is currently a known bug when someone has more than 1000 HVR1 or 12 marker matches, it times out. I hope the upgrades help. The show matches by project is on your toolbar, under the apps option, under advanced matching. Look at the screen shots. On that page, it’s at the bottom of the options where you select entire data base or matches by project. The site are down right now for maintenance so I can’t go and check, but I do this all the time.

      • Ah, I don’t know why I was expecting it to be on a different page. Doh!

        The site is back up, for me, and the bug is still there. Le sigh.

  3. iI have lots of DNA tests now and I am ready to start using it to confirm my genealogy. I can’t find in any of your past posts where you foundthe information on The length of segments, start, end and on what chromosome that determine a match. How do I determine which side of the family my genes come from.? Do I have to go back to the basic four letters?

  4. For a time, I could not find much about my maternal lineage due to sparse records in 19th Century Arkansas and in Oklahoma prior to statehood. So I took the full mtDNA test at FTDNA and found that my type is U6a3b. It is very rare. There are only six people in the data base with my type. They came from England Ireland and Scotland. My closest relative is one genetic distance from me.

    It appears that my lineage originated in the near East, migrated to the Maghreb region of North Africa and then to Iberia. From there, bronze age trade routes took it to the Western British Isles after the ice age receded.

  5. Thank you for the article. I was curious about two Full Sequences that I have. One is from Germany, surname Wagner. I do have a Wagner branch on my maternal tree. The one from Ukraine I am not sure about. Bozdugan is the one from Ukraine (Bavaria?). I also have a 2 step from Sardinia Italy which I am not sure how we are related. The one from Ukraine and Italy might be too far back to find a common ancestor. I did read that H13a1a1 is found throughout the southern coast of Europe.

  6. Dear Roberta, I read with a big interest your writing about triangulation. Can the method be used to determine MRCA, if I use for triangulation mine kit and my 1 st cousin, to determine the 3rd person?

    Henryk Gruder

    • To some extent. You can know that they are from that line, someplace, but not that the third person shares your MRCA with the first cousin. And that’s assuming a larger segment as well.

  7. Please read all the way through to fully understand the problem we have found in properly identifying eight WWII Airmen, four each died in two different bomber crashes. According to the 8th Army Air Force records and survivors testimony, a B-17F crashed about 30 miles west of Strasbourg, France, on 6 September, 1943. During the next two hours, six more B-17Fs from the same Bomber Group were shot down, for a total loss of seven in France that day. The first B-17F lost in France was reported in the official mission report, to have been sighted in a tight left spiral with its nose and left wing on fire. The left waist gunner and the radio operator bailed out together. A German fighter buzzed the radio operator and collapsed his parachute and he fell to his death. The left waist gunner identified him, where he landed and I have been to that location. Four men died in that loss, one fell to his death and three were aboard the B-17F when it crashed. One survivor testified, the left wing broke off and fell past him when he in the air. Two hundred and sixty-one miles to the west, a B-17F crashed, there are two photographs of the crashed bomber and both wings are still attached. However, due to a single ID Tag found in his flight clothes, although the Germans gave them four unknown remains the French cemetery workers found an ID Tag and that remains was buried with that identification. When American Graves Registration relocated the remains to an American Cemetery, they identified all four, based on the found ID tag and not the location of the crashed B-17 they were recovered from. The ID Tag actually belonged to the man who had bailed out of the B-17F and fell to his death, near Strasbourg. Thus, all four of the men who did die at the seventh crash site, along with their B-17G, remain on the Missing In Action Lists. When Graves Registration finally arrived at the crash site of the B-17F near Strasbourg, the documentation that would have correctly identified the three dead near the crash site of B-17 was missing. However, they did have the records of a crashed B-17G with three MIA dead involved and it is obvious they also misidentified the dead from the B-17F crash site as the dead from a MIA (with three dead aboard) B-17G. Which leaves the actual crash site of that B-17G, still unaccounted for. The physical evidence distance of the Official Last Sighting of the bomber near Strasbourg and the time until the seventh bomber with four men aboard makes it impossible for the dead found at the seventh crash to be correctly identified as the crew lost near Strasbourg. DPAA, our official accounting agency, refuses to reopen the identity of the eight dead at both crash locations. However, a female direct relation agreed to have the official grave of her uncle, the man who fell to is death, opened so DNA evidence could prove it was not her uncle. We did disinter her supposed uncle’s grave and we did have two different organization conduct DNA matching. Both found the remains matched with a 95% matched and 5 % error. It appears to be impossible, however, the head DNA person at the second matching location, told me that there are people who are 95% matching DNA and yet, there is no direct, provable relationship, the other 5%.. Based on that, I have ancestor researched both men and found both had G-G-G-(+)grand-mothers who left the same village in Poland in the late 1400’s, when a Pogrom forced all the Jewish people to flee. We have no way to prove or disprove they were sisters, cousins or otherwise related. The Jewish history before that time was lost when all the temple records were destroyed. We are attempting to force DPAA to reopen the miss-identification, which they currently refuse, using the excuse that the American Public cannot handle the truth, that such mistakes were made and many families with questions will demand correct answers. Any possible help in providing the 95% does not prove the remains found inside a crashed B-17F cannot be the man who fell to his death, will be greatly appreciated!

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