Tuesday, November 8, 2016

Doubly Related

Whenever people mention having relatives who were related in more ways than one, it seems the immediate reaction is one of disapproval. Cousins marrying cousins is a situation that does come with not only disapproval, but a certain risk of inbreeding.

And yet, when we trace back far enough in our trees—especially in those families with colonial roots or from endogamous populations—we may be more likely than we think to uncover close relationships.

I've certainly discovered such connections in both my mother-in-law's tree and my mother's tree. Both women came from families which have been in this country since at least the 1700s. And that makes sense. Think of it: with a limited population from which to choose suitable mates, a family was likely to tend toward known entities. Back in the 1700s, cousins marrying cousins wasn't a rare thing.

Fast forward to the 1900s. By then, second or third cousins marrying each other in a small farm community was still bound to happen.

Now, the question is: how do we represent that sort of double connection in the new family trees we post at Family Tree DNA? I mean, here I am, trying to update my records there, and I encounter a match for my husband estimated to be within the range of second to fourth cousin. As it turns out, this person connects with my husband in not one way but two. One of those ways calculates to be out to sixth cousin, once removed. The other way links to a set of most recent common ancestors who were the matches' sixth great grandparents—so, once again, a distant relationship, this time of seventh cousins.

So, what do you do with such calculations when you are doubly related? Does the second relationship add some sort of exponential afterburners? How do two familial relationships—one at sixth cousin once removed, the other at about seventh cousin—show up in our DNA matches as an estimated range of second to fourth cousin?

More importantly, how do we show these double relationships on FTDNA's charts? In their latest phase, customers may now link their matches' lines to their own tree—and then, with special clicks to verify the identity of said matches, confirm that mutual line of relationship.

But that routine can only be done once. Entering the second line of relationship will not allow the match to be confirmed in that tree. Apparently, you only get one chance to click on that special linking button.

So for now, with this first instance of double relationship that I've worked on in the updated FTDNA dashboard, I'll have to settle for this particular match being recorded solely as that solitary sixth-cousin-once-removed relationship and no more.

I'd think someone would want to examine just what happens to DNA test results when the subjects are related in more ways than one. Someone, that is, besides just me.


  1. Interesting...you are on the cusp of a software change or should be...certainly someone thought of this? You need another link:)

    1. Hopefully, this will be something in the works. I'd think this would be an interesting question to pursue. It certainly isn't a rare occurrence.

  2. I think they just never thought of it - now whether or not they can easily change the software is a different story.

    1. True, Iggy. The software change is a big issue. And the company has just rolled out quite a few changes already.

      But I can always hope :)


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