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Why David and not Dorothy?

AncestryDNA has taken the position from the very beginning that individual users of its DNA product don’t need certain information.

We don’t, it contends, need to know what segments of DNA we might share with a person who is our match in the AncestryDNA system.

And we don’t, it contends, need to know who else in the AncestryDNA database we and a match might have in common.

AncestryDNA will tell us everything we need to know, it contends, by giving us DNA Circles.

compareDNA Circles, it tells us, “re-imagines what matching can do. It goes beyond finding a common ancestor with your DNA matches and can link you to additional AncestryDNA members with the same common ancestor thus creating a Circle of people who are all related.”1

We don’t need to have any of the information that explains the links between the people in the DNA Circles because, after all, AncestryDNA has “trained the computer to do the hard stuff like DNA matching, tree comparisons, and triangulation for you.”2

So why am I sitting here this morning, thoroughly frustrated and unable to figure out one simple question: how can a third cousin be in a DNA Circle for our both of our shared 3rd great grandparents and in a DNA Circle for our shared 4th great grandfather but not in a DNA Circle for our shared 4th great grandmother?

Our mutual line of descent is shown in the graphic above. Both of us have Martin Baker and Elizabeth Buchanan as our third great grandparents, and David Baker and Dorothy Wiseman as our fourth great grandparents, and both of us have all of them in our Ancestry family trees.

As for our shared fourth great grandmother, David’s Ancestry tree lists Dorothy as born 5 Feb 1765 probably in South Carolina and died 23 August 1855 in Bakersville NC. Her parents, he says, were William Wiseman and Mary Davenport.

My Ancestry tree lists Dorothy as born 5 Feb 1765 probably in South Carolina and died 23 August 1855 in Bakersville NC. Her parents, my tree says, were William Wiseman and Mary Davenport.

In other words, the tree data is exactly the same.

That sameness shows up in the DNA Circles for our third great grandparents Martin and Elizabeth — everything matches. It gets wonky when we get to that fourth great grandparent generation.

I have 17 people in my DNA Circle for David Baker and fewer for Dorothy Wiseman. That makes sense because David Baker had two wives, and some of those in the David Baker circle are descended from the first wife, Mary Webb, and not Dorothy, who was the second wife.

Of the six people who are in the David Baker circle but are missing from the Dorothy Wiseman circle, five fall into the category of “descended from Mary Webb.”

One doesn’t.

That’s my third cousin David.

And AncestryDNA gives me absolutely no idea why.

I suppose it could be because cousin David matches me and some other members of the David Baker circle but not some of the other members of the Dorothy Wiseman circle.

That could be, but I can’t tell, because AncestryDNA doesn’t give me a way to see who else cousin David and I have in common.

I suppose it could be because cousin David matches me in a different segment than I match the members of the Dorothy Wiseman circle.

That could be, but I can’t tell, because AncestryDNA doesn’t give me access to any of the segment data to make that kind of analysis.

So cousin David and I are a match, and we both have the same descent from the third and fourth great grandparents, and I’m in circles for all four — and he’s in my circles for three of the four — and I have no idea why.

So tell me, once again, why I don’t need those analytical tools, AncestryDNA.

Because I can’t square these circles.


SOURCES

  1. Anna Swayne, “New AncestryDNA Technology Powers New Kinds of Discoveries,” Ancestry Blog posted 20 Nov 2014 (http://blogs.ancestry.com/ : accessed 28 Mar 2015).
  2. Ibid.
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