Adoption Searches Using DNA

>> Thursday, November 21, 2013

The method some of us have developed in the DNAAdoption group  for working with Autosomal DNA results is pertinent to genealogy searches as well.

You will find a methodology and other documentation on
There is a yahoogroup DNAadoption, that provides interchange of information among individuals working with their DNA results.

Despite what the ads for DNA testing look like, in almost every case, it takes a great deal of work to uncover the connections. However, the methodology does work.

Usually one gets a list of DNA cousins spread over many generations. However, recently one lucky person logged in to see her results and found that her birth mother had been tested and identified! This is everyone's dream of course.

The usual method is to identify the closest cousins. The longer the length of overlapping DNA segments, the closer the relationship. Then we try to get trees for these cousins and identify how they are related. Where the have a common ancestor, the person who is seeking also has that ancestor. Working down through trees looking for a person who might have been in the right place at the right time, it is necessary to follow all offspring of all generations. This can get pretty messy to follow, so I break out a separate tree using genealogy software of all descendants of that common ancestor.

I am working with a woman who has been looking a long time. She went a couple of years without any significant results from her DNA testing, but in the last couple of months has gotten results from 8 third DNA cousins. It is now a matter of hoping for good trees and following down these trees looking for the point where they once again intersect.

I have now been able to add people who tested with all three systems to one spreadsheet for comparison. I do this by downloading the FTDNA and 23andme files from I use data in FTDNA's chromosome browser list and 23andme's FIA list. The only data you will have in the FIA list is that from people who have shared genomes with you. I then ask Ancestry matches to upload to where I can see the chromosome numbers. Now I can compare the data of what once seemed like apples and oranges.

I hope in the next blog to give you some success stories.


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