Distant DNA Matches: What to Do with Them

Diahan Southard

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What can you do with more distant DNA matches, with whom you share fewer centimorgans and with whom a common ancestor isn’t apparent? Diahan Southard says to consider these three things.

Recently I received a great question from Ellen:

”I have several matches where the shared DNA exceeds 30 sometimes 50 cMs. I have ‘baked more than a few cakes’ in trying to identify the common ancestor without success. What are some possible explanations? Are there any strategies I could employ? I have tested any available family members on these lines of descent.”

If you are having a similar struggle, here are three possible explanations.

1. You don’t share a recent common ancestor.

Even though your total amount of shared DNA is in the range to be a third or fourth cousin, you may not actually share a recent common ancestor. You could just share a lot of common DNA because you are both Irish or Italian. One clue in this situation would be to look at the longest shared piece of DNA. In general, if you share most of that small amount in one piece you are more likely to share a recent common ancestor than if you share that amount in multiple small pieces.

2. You’ve got the wrong generation of connection.

Your generation of connection is the generation in your match’s tree that holds your common ancestor. So, with your first cousin, the generation of connection is their grandparents; with a second cousin their great grandparents, and so on.

This works out just fine and dandy as long as you and your match are on the same generation. But when your match is much older or much younger than you, you often have some kind of removed relationship. Meaning, your generation of connection isn’t equal for both of you.

The short of it is, if the company has told you a match is your third cousin, and you are looking at all of their 2X great grandparents (really, they know ALL of them?) and you don’t see anything familiar because you know ALL of your 2X greats (again, you really do know ALL of them?) it might be because your match is removed from you. If your match is a generation younger, your generation of connection with them is NOT their 2X greats, but their 3X greats! Yikes! So you would need to look at their 16 3X great grandparent couples to find a common ancestor.

3. Theres a disconnect in genetics and genealogy.

If you have verified that this is not a distant match (because you have a nice big piece of shared DNA) and that you have correctly identified the generation of connection (they aren’t removed), then it is possible that the genealogy you see on your match’s tree does not match their genetics. Or, the genealogy you see on your tree does not match your genetics.

If you can see several DNA matches who connect at a common ancestor in their trees, but you do not yet have that ancestor on your tree, well, it might be that your DNA is trying to tell you something about your family. And especially if those names on the trees of your matches are in the same location as your family. You might consider that your DNA is revealing a new (or different) ancestor to put on your tree.

Susan just shared a story on our blog about using her DNA matches to identify a previously unknown ancestor. We love stories like these! They show you how everyday people are using DNA to shed light on their family history mysteries.

Working with DNA Matches

Reaching out to your DNA matches, no matter how distant, can sometimes feel like asking someone on a date, you might feel a little bit nervous, maybe a little exited, and you’re not sure how they’ll respond. Lucky for you, we’ve compiled all of our best tips for contacting DNA matches into one free guide!

I want my free guide to contacting DNA matches

<a href="https://www.yourdnaguide.com/author/guideyourdnaguide-com" target="_self">Diahan Southard</a>

Diahan Southard

As founder and CEO of Your DNA Guide, Diahan Southard has been teaching people how to find family history answers in their DNA for several years, and she's been in the genetic genealogy field since its infancy. Diahan teaches internationally, writes for popular magazines, consults with leading testing companies, is author of Your DNA Guide–The Book, and producer of Your DNA Guide–the Academy, an online learning experience.

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8 Comments

  1. Christopher Schuetz

    Great tip to check whether removed.
    So far, many of my matches at mid-distance (around 3C to 4C) have not had trees where my DNA matches them. My best success has been to 1)message them, 2)maybe they have another tree elsewhere 3)maybe a mutual match I already have made contact with does know something about them.
    For many people messaging just does not work for many reasons. It helps to be creative. And one success often leads to another. I just had two hard-won contacts at 3C come back to me with more family history and cousins they found this year.

    Reply
    • Diahan

      Christopher, thanks for sharing this hopeful experience! Patience and persistence!

      Reply
  2. EJ Blom

    Perhaps another strategy might be to cluster your DNA matches and see where the distant matches appear? That might provide clues on where to find the common ancestor. You could do also a targeted clustering, taking the shared matches with the distant match, and next take the shared matches of these shared matches. Plug them into tools that can identify clusters (for instance https://www.geneticaffairs.com/features-autofastcluster.html) and hopefully you’ll discover some clusters.

    Reply
    • Diahan Southard

      Hi EJ, thanks for sharing. Clustering tools are certainly another option.

      Reply
  3. Chris F

    Very good blog. =)

    I seem to have a wide range of DNA matches on my mom’s side. The cM counts are widely varied and honestly made me scratch my head a bit. If I didn’t confirm it via a paper trail, I never would have known that a cousin who shares 7 cMs with me was really a 3rd cousin once removed. I sorted that out before Thrulines became a thing. It helped that she had a picture of our ancestors. They were sisters. And it also helped that my mother shared a bit more with her.

    It’s always going to be wild because of our Quebecois origins. There was a bit of endogamy in Quebec in the 1600s and that is going to create some varied matches. I know I talk about this scenario a lot. But, it’s still going to be wild to me.

    Just wish I was able to figure out closer matches. Perhaps some day I will. Great blog and great tips to think about!

    Reply
    • Diahan Southard

      Thanks for reading, Chris! Keep plugging away at those connections. I am confident that you will figure out out one day.

      Reply
  4. Anna-Karin S

    I and my half firstcousin AW and my newfound halfniece CJ has one common ancestor my paternal grandmother Karin O. Some of Karin O: s ancestry is a bit mysterious. I have tried to find out and triangulate those matches we all 3 have in common and those I and AW have in common. There are several of them but only 4 are around 25-40 cm most are around 8-20 cm in 1 or 2 segments. Is it possible to figure out any of our common ancestors with so little cm in the matches. I have spend many hours researching the ancestors of very distant matches

    Reply
    • Diahan

      The important thing to focus on is the generation of connection. So starting with those 4 matches, have you pushed their genealogy back to your generation of connection? What you are hoping for is that if get all four of them back to that generation that you will see a common ancestor among those four. If you don’t, well, then it is likely have a more distant relationship that you realize.
      But really, you have identified what you need to do: spend hours doing other people’s genealogy. The alternative is to wait… Just wait for better matches to come along.

      Reply

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