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The X match

One of the most exciting things about working with DNA testing in genealogy is how fast things are changing, and how much we can learn with new tools that are becoming available.

And boy did that make The Legal Genealogist‘s heart glad this past week.

DNA.chartBecause we’re pretty confident now that we’ve found Charlie, a missing member of the family, thanks to XDNA matching and a really neat new tool called the Autosomal DNA Segment Analyzer — ADSA, for short.

Let me set the stage here.

My third great grandparents, Martin and Elizabeth (Buchanan) Baker have long been thought to have had six children — four sons and two daughters.1

Four of the children — sons David Davenport Baker, William Baker and Josiah Alexander Baker and daughter Martha Louisa Baker (my own 2nd great grandmother) — are now well documented.

But two of the children — son Charles and daughter Susan — had somehow fallen into oblivion. Where had they gone? What had happened to them? The available documentation didn’t give us an easy answer.

Some months ago, my first cousin and fellow genealogist Paula picked up on the available clues and started out on Charlie’s trail. She found a good candidate, one who unfortunately died young, in Kaufman County, Texas, in 1869.2

Although she found children that looked like they were Charlie’s, including an oldest daughter, Susan, the records just weren’t enough to say that this was our Charlie.

And then I took my first look at the new tool, the Autosomal DNA Segment Analyzer. The ASDA is part of the set of tools at DNAGedcom, a major DNA tools site developed for initially the benefit of adoptees trying to use genetic genealogy to discover their own biological identities and now available to all. Rob Warthen, Karin Corbeil and the whole team at DNAGedcom are just terrific.

Their new tool ASDA was developed by Don Worth, a retired IT professional. What it does is take your raw data and your in-common-with matches from either 23andMe or Family Tree DNA ((correction: this only works with Family Tree DNA data now!) and plot them out in a graphical presentation that makes it so very much easier than it’s ever been before to spot patterns.

You have to register on the site to use it, but everything including the ASDA is free. There are instructions on how to use the ASDA and some sample output to play with before you consider using your own data.

And this tool only works with autosomal DNA results — results from the Family Tree DNA Family Finder test or the 23andMe test (see correction above).

But let me tell you: it’s one thing to see a match list, or even a list of matches you have in common. It’s something else again to see a chart like the one you see above — all nicely and neatly color coded to tell you that all these folks match you and match each other in the same place on the same chromosome. That tells you this is a pattern to follow up on.

So I started playing with the tool, checking out different family members and their results. And one of the patterns that started coming up was a match to a new cousin, Joe. And particularly intriguing was the fact that he has an XDNA match to two of my cousins.

I sent an email off to his contact address, got a response from his lady who’s the family genealogist, and an invitation to see his tree.

And he descends from that Charles Baker… through that oldest daughter Susan.

Now the autosomal evidence is good. He matches all the people he should match to be a Baker cousin match. But we have just enough unknowns on that side of the family to want more.

So I took this new DNA cousin’s line of descent and that of the two cousins to whom he has an XDNA match, and plotted them out on The Genetic Genealogist Blaine Bettinger’s great XDNA match charts.

You see, because of the way the X chromosome is handed down, there are fewer ancestors who could possibly have contributed DNA to that chromosome. In a male, only his mother’s ancestors could have contributed since he only gets an X from his mother (he gets the Y that makes him male from his father).3

If we were right here — if our new cousin’s Charlie Baker was our Charlie Baker, son of Martin and Elizabeth — it would have to show up on those charts. Each of the cousins would have to have a way for the DNA to travel down the generations from our common ancestor to them.

For every cousin, the XDNA had to come down five generations in a particular way. It didn’t have to be exactly the same way for each of the three men, but there were some paths it couldn’t travel — it could never make it, for example, if there were two males in a row.

I started coloring boxes and held my breath…

Take a look.



Dick and David are my known cousins. Dick’s (and my) great grandfather is the older brother of David’s great grandfather. Joe is our new DNA cousin.

In both cases, the yellow is the path the XDNA would have to take between the person being tested and Elizabeth (Buchanan) Baker, who is circled in red.

And the path works for them all.

If Joe’s Bakers had been on his father’s side, we wouldn’t have gotten an X match at all. If the Bakers had been on his mother’s father’s father’s side… it wouldn’t have worked. Or if Dick’s or David’s Bakers had been on their mother’s father’s side, it wouldn’t have worked.

But the path works for them all.

Hello, Charlie. Welcome (back) to the family.


  1. Elma W. Baker, The Rugged Trail, Vol. II (Dallas, TX: p.p., 1973), 23, citing family Bible records and individuals who reported information to him.
  2. 1870 U.S. census, Kaufman County, Texas, mortality schedule, page not shown on image, Chas. K. Baker; digital image, ( : accessed 1 Feb 2014); citing National Archive microfilm publication T1134, roll 10.
  3. See generally Judy G. Russell, “X marks the spot,” The Legal Genealogist, posted 5 Jan 32014 ( : accessed 1 Feb 2014).
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