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Another open letter to my AncestryDNA cousins…

NOTE: This blog’s recommendation of GEDmatch has been withdrawn due to privacy issues. See “Withdrawing a recommendation,” The Legal Genealogist ( : posted 15 May 2019).

Please, please, please, dear cousins.

Please share your AncestryDNA autosomal testing data with your cousins.

You know.

People like me.

DNA.helixYes, I have tested with AncestryDNA.

Yes, I know that you and I match as second or third or fourth cousins there.

Yes, I know your family tree data and my family tree data seem to be pointing in a direction towards a match in this line or in that line.

But what neither of us can tell using the AncestryDNA site is… is that the right line?

The problem is that you and I might have it all completely wrong. Your tree, or mine, might be in error. We’re cousins, yes, but it may be in — say — the Robertson line and not the Jones line. Or the Cottrell line, not the Pettypool line.

To have a chance to nail it down with any degree of confidence, we need to combine the paper trail research with the actual DNA data: what DNA exactly do we really share?

The problem is, there’s no tool available at AncestryDNA that lets us take a look at the actual data:

How much overall DNA do you and I have in common? Are we at the high end or low end for second cousins? Are we really as likely to be second cousins once removed? Should we be looking a generation away for the common ancestors?

How big are the DNA segments we share? The bigger the segments, the more likely they are to be the result of actual shared inheritance, and not simply the roll of the genetic dice. Some segments are just too small to be meaningful.

Where are the segments we share, on what chromosomes? You and I aren’t likely to be cousins in the Robertson line if you and I don’t share any segments with any of my many Robertson kin who’ve tested. We may need to look at other possible lines to find our common ancestors.

So please… please, dear cousin. Share your actual testing data. There are two ways to do it, and both — at a basic level — are free.

First, please upload your data to the website I wrote about GEDmatch back in 2012 and even then called it a DNA geek’s dream site.

The only thing that’s changed since 2012 is that there are now some additional, fee-based goodies if you’re willing to pony up a little cash that I’m just starting to play with. But the overall basic functionality is still free. And it lets you really analyze your DNA results against those of others who’ve also chosen to upload to GEDmatch.

Read more about GEDMatch in my 2012 blog post here or in Kitty Cooper’s blog post here.

And second, please upload your AncestryDNA autosomal test data to Family Tree DNA. What’s called the Autosomal Transfer Program has two flavors, one paid and one free. The paid option, which only costs $39, is by far the better choice, but even the free one can get you started.

Family Tree DNA is a genetic genealogy DNA testing company that does autosomal testing as well as YDNA and mitochondrial DNA testing. What it offers that AncestryDNA doesn’t for autosomal testing is analytical tools. There, you can see how much DNA you have in common, how long your shared segments are, what chromosomes they’re on, who else you and a match share as a common match, and more. These are, really, the basic building blocks of using autosomal DNA data as part of good genealogical research.

The transfer system is explained on the Family Tree DNA website here, and there’s more that’s been written about it that you can read at, for example, Roberta Estes’ DNA-eXplained blog here, or Blaine Bettinger’s The Genetic Genealogist post here.

See, I really do want to work with you, cousin. But we can’t just click on shaky leaves. We need to look at the data. So… share with me, okay?

And if you’re that particular second cousin… I might even pony up the $39 fee for you…

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