Friday, August 11, 2017

A 245 Centimorgan Mystery: DNA Triangulation At Work

With my recent excitement over DNA discoveries (welcome to the family, new first cousin!), I've spent the past week or so sending my newest cousin photographs, family health information, and family history. I have more to send - how can one even explain all of this in mere weeks? But I want to give her space to process everything.

So as she's working on learning more about her newly-discovered biological family, I am turning my attention to the shared match I mentioned in my post about my new cousin.

As I said at the end of that post, this 245 cM match also matches my new cousin. My new cousin only matches me through a very specific line, which means my mystery match can only share one of two sets of great-great grandparents with me:

Edward Henry Blake and Ada Estella Gay

or

Erastus Bartlett Shaw and Emma Anna Murphy

I know this thanks to triangulating with my new first cousin match. My first cousin only shares my paternal grandmother, not my paternal grandfather. Why? Because my paternal grandmother had two marriages. She had two children from her first marriage (my oldest uncle and my aunt) and two children from her second marriage (my second uncle and my father). My new first cousin descends from my oldest uncle.

So since my 245 cM mystery match shares my first cousin as a match, I know it must be through an ancestor of our grandmother, Barbara Estella Shaw.

With a match of 245 cM, I know we're in the second cousin range. I've been in touch with this match and based on her age (she was born in 1947; I was born in 1974), I'd say we're looking at a once removed relationship in there.

It will help immensely when my father finally sends in his DNA test, but considering the closeness of the match, this would put her in first cousin territory with my dad. Maybe a first cousin, once removed.

That helps put this in perspective, but it's interesting to note that my grandmother only had 4 siblings and I'm only aware of 2 of them having children. I'm not saying there can't be surprises there, but that would mean this woman is (quite possibly) adopted and not aware of it.

So you can see it's rather tricky territory, as Judy Russell recently noted. (As a side note, I'm thrilled that Judy Russell is speaking at the Nebraska State Genealogical Society conference next year. Oh yes, I will be there!)

Since I'm not ready to pursue that idea just yet, the first thing I'm doing is backing up to my father's grandparents. This brings me to Harrison Clifford Shaw and Nina Gertrude Blake. I'm exploring the possibility that somewhere in my family is a mis-attributed parentage.

However, all I can do at this point is speculate. I am considering the mirror tree concept, but I do feel certain there's a mis-attributed parentage somewhere among our trees. Whether hers or mine, I won't know until I dig further.



Copyright (c) 2017 Wendy L. Callahan

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