Friday, December 18, 2020

The Story of Bernadette: Part 6 - No Close DNA Matches

Using online DNA data bases to research NPE results

By October of 2018 I was working with two more adoptees on open cases. After scouring test results of NPEs, it became clear that each story unfolding through DNA was singular and intriguing. I looked forward to viewing Bernadette’s matches as her background was very different from the rest of my NPEs. She had no idea whether or not her parentage was accurate or if the questionable incidences from her past were true. All of my other adoptees knew for a fact they were searching for their birth families. But Bernadette was one big question mark!

Since Bernadette’s son, Jim, had taken care of all the details involving Bernadette’s test kit, I asked if I could be added as a manager on her account. This would allow me access to all of Bernadette’s DNA information (ethnicity, cousin matches, and family trees) and the ability to use DNA tools such as searching and filtering cousin matches, color coding and Ancestry’s ThruLines. Full access to an NPE’s results is essential in order to correctly sort, research, and analyze their genetic background.

As an account manager and with Jim’s consent, I also had the ability to download Bernadette’s raw data file. This gave me the option of uploading her DNA to other data bases in case I found no helpful matches at Ancestry, necessitating that we look further afield.

Well I can’t say that I was surprised at Bernadette’s results. As I suspected, there were no close family or first cousin results. Nor were there any second cousin results. This was going to be harder than I thought! Some of my other cases had been solved in a matter of days or even hours, as those results clearly pointed to a birth family. Not Bernadette’s results!

The closest cousin match shared only 155 centimorgans (cMs) of DNA across seven segments. In comparison a niece or nephew match would share an average of 1740 cMs across about 50 segments; a first cousin match would share an average of 866 cMs across a possible 30 to 40 segments. Bernadette’s closest cousin match was well below what I had hoped for.

This was disappointing as AncestryDNA placed the relationship of her closest match in the 3rd to 4th cousin range, meaning a common ancestor could be three to four generations in the past. Estimating any DNA relationship past first cousin can be tricky as the amount of shared DNA decreases with each cousin level and generation. It is especially difficult for distant cousins sharing a small percentage of DNA. Testing companies usually offer broad and fairly basic relationship estimations such as 4th to 6th cousin. However, you will find that the more distant the match, the more options you have for relationship levels. Few testing companies offer estimations such as 3rd cousin, twice removed or half-great aunt. They simply don’t go into depth explaining the possibilities, and most people accept the broad relationship estimation attached to their cousin matches as accurate.

I knew better than that! For a precise relationship estimate, I always refer to: DNA Painter Shared cM Project, a free online tool created by noted genetic genealogist Blaine T. Bettinger. You can find the latest version here: https://dnapainter.com/tools/sharedcmv4

I entered Bernadette’s cM quantity shared with her closest match (155 cMs) and found the most likely relationships were:

  •         half 2nd cousin
  •         2nd cousin once removed
  •        half first cousin twice removed
  •        first cousin three times removed

Yikes! None of these relationships would be simple to trace as they all spanned several generations and could take me down the rabbit hole of numerous family lines.

OK – I had my work cut out for me. This was not going to be an easy task attempting to unravel the past and find the truth hiding behind Bernadette’s DNA results.


Researching DNA results for adoptees


 


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