Wednesday, April 20, 2022

Let's Make a Match, DNA Style


Quick DNA question: What does it take to make a DNA match?

Simple answer: Two family members who are willing to test their DNA.

The catch: You never know who those distant cousin matches will be until both you and they test.

When I first began mounting that genetic genealogy learning curve, that question gave me grief. Here I was, with an account at the three major DNA testing companies of that time, filled with matches whom I couldn't place on my family tree. Admittedly, they were mostly fourth cousins, meaning that both they and I needed to have a pedigree chart completed to at least the level of third great-grandparents on all branches.

I stopped beating myself up over not being able to place these cousins on the right family twig when I realized there were gaps in our family's story. Let's rephrase that: back then, there was a lot that was missing from the picture. That was what first motivated me to study the collateral lines of my ancestors, and to religiously add them to my family tree.

More than that, though, was the realization that you can't have that magic match—you know, the one who will reveal all the answers about your brick wall ancestor—until the descendant of your brick wall ancestor coincidentally decides to test. If that cousin doesn't test, the two of you will never have a match.

Since that is all out of our own hands—well, except for those wunderkinds who actually know all their fourth cousins—there is nothing we can do to control such an outcome. That's when I let it all go. I stopped berating myself over not being able to connect matches, and started building this mammoth, oversized tree.

On the flip side, with the advent of's ThruLines tool, I see that scenario stood on its head. Take my current research goal of examining the roots of Perry County, Ohio, settler Nicholas Schneider. If I check my husband's DNA matches using ThruLines, I can look up his third great-grandfather Nicholas and see just which of his many children's lines produced DNA matches for my husband's account.

It is interesting to see the variance in how many DNA matches are yielded by each child of Nicholas and Anna Elizabeth. Unsurprisingly, since my husband descends from two of Nicholas' sons—Jacob and Simon—of course there will be DNA matches connecting us back to those founding immigrant ancestors. As of this writing, there are seventy eight people descending from Jacob Snider who match with my husband. Of Simon's descendants, thirty nine are his DNA matches.

The universe of Snider matches is not limited to descendants of those two sons. As we observed on Monday, there were at least five other children who could have been ancestor to my husband's Snider matches: Lewis, Joseph, Mary, Peter, and Conrad. Yet, how varied are the counts for each of those lines' matches. While there are twenty matches claiming Lewis as their ancestor, there are only four tracing back to Joseph. Mary had ten, Peter claimed thirty three, and Conrad nineteen.

Was this just a function of one progenitor having more children than the others? That hardly appears so. I think, once again, it all goes back to that definition of a match: maybe more of Jacob's children decided to test their DNA than the others. I don't suppose there would be any way to predict this. There certainly is very little control we could have over such a result. Our matches are a gift over which we have little influence, past the first couple generations of our own family line.

Of course, then there are the puzzlers...the ones whose ancestral connection leads to a person not found in our third great-grandparents' paper trail. And I'm not necessarily talking about what has politely but awkwardly been labeled "Non-Parental Events." I'm simply referring to people who do share our DNA, but not the same vision of our joint family tree.

In this particular Snider case, my husband has two DNA matches who claim ancestors supposedly the children of Nicholas and Anna Elizabeth. Only, they weren't. Not, at least, as far as I can see. For such instances, there are two options: search to see whether I've missed something, or study that ThruLine proposed line of descent to discern just where that match's tree might have crossed branches.

That, of course, may require a little tree-building exercise. Do you ever find yourself building out a proposed tree for a DNA match like that?  

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