Thursday, May 31, 2018

A refresher on using atDNA

The reason we do autosomal testing for genealogy -- with Ancestry, Family Finder at Family Tree DNA, MyHeritage, and 23andMe -- is to learn where our DNA matches fit into our trees. Our closest matches, at the top of our match lists, are parents, siblings, aunts, uncles, nieces and nephews. The rest are cousins -- first, second, third, etc., or half-cousins, etc. Once we find a match that fits in the family of GGGGGF Tom Jones and his wife, for example, we work together with the match to find our Common Ancestor. Then we look for other matches that we share with that person and expand Tom Jones' genealogy by adding generations, up and down. So we're always looking for people who match us and other people.

We want to find those who match bits and pieces of our DNA. To do that, we use tools like Gedmatch, DNAPainter, RootsFinder, or the new DNA Matrix in Charting Companion. Ancestry gives us a headstart with its Shared Matches. FTDNA provides chromosome mapping, a matrix tool,  ICW, its version of Ancestry's shared matches, and a phasing tool as part of its Family Tree feature. MyHeritage and 23andMe both provide full triangulation. For many more tools and many more matches, you must use Gedmatch.

The best strategy today is to test with Ancestry, which has the largest database, then download your raw data and upload that file to Gedmatch, FTDNA, and MyHeritage -- for free! You may want to pay for full access to FTDNA for $19 and occasionally spend $10 for a month's access to Gedmatch, but these are optional.

And if you're still befuddled, read this book by Blaine T. Bettinger: The Family Tree Guide to DNA Testing and Genetic Genealogy.