Friday, January 8, 2021

The Story of Bernadette - Part 10: Using Ancestry ThruLines to Identify Paternal Lineage

AncestryDNA ThruLines Graphic
When it comes to genetic genealogy as with family genealogy, the best place to begin is always with what you know to be true. Since I had researched and compiled a three to four generation tree for Bernadette based on the parents who had raised her, this was my obvious starting point – the objective being to either prove or disprove their known identity.

I quickly put together a grandparent lineage chart using the surnames from Bernadette’s tree. And, of course, immediately a problem emerged. A number of surnames overlapped two or more columns on my chart! Since both of Bernadette’s assumed parents came from a historically endogamous community located in an alpine valley, it was obvious that all four of her assumed grandparent lines had intermarried for centuries and were interrelated. This is not unusual for an endogamous society, but it does pose a nightmare for a genetic genealogist attempting to sort out DNA results!

I scanned the first twenty to thirty matches and was relieved to see a few surnames that matched Bernadette’s paternal side, with several that coincided with her maternal lines. But remember, these were for the most part, all distant cousin matches sharing a small percentage of DNA. And it was apparent from the mutual surnames that Bernadette’s closest cousin matches also shared her endogamous heritage.

This was both a blessing and a curse! A blessing because Bernadette’s DNA matches were proving that one or both of her parents were from the same community, therefore narrowing our scope of possible birth candidates to her specific ethnic and societal group.  But also a curse because now we are attempting to sift through cousin matches most likely related to both Bernadette’s paternal and maternal ancestry with little distinction between grandparent lines.

Luckily Bernadette’s first few matches, although distant, were connected to family trees. Some even showed a “common ancestor” connection based on shared ancestors noted on Bernadette’s tree and their tree. Since I had linked Bernadette’s tree to Ancestry’s ThruLines tool, it only took a few minutes to identify the common relative of her closest matches along with their relationship to Bernadette.

Of Bernadette’s top ten matches, four were direct descendants of her assumed paternal grandmother’s line, three were related to her assumed paternal grandfather’s lineage, and three were related through both of her assumed paternal grandparents. Since Bernadette’s closest match (sharing 155 cM) was connected to an extensive tree, it was easy to determine their genealogy relationship as second cousin, once removed with Bernadette being the elder of the two. 

DNA was certainly pointing us in the direction of Bernadette’s birth father being the man who had raised her, which would disprove her questionable baptismal record.

AncestryDNA ThruLines Graphic



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