Saturday, August 18, 2012

Some Interesting Genetic Matches

Here are some of my more remarkable genetic matches over at 23andMe.

This genetic cousin matches me on three segments, but my mother on only one and my father on none.  I probably received the other two chromosomes from my mother.  The match on chromosome 9 is perhaps just under 5 cM (centimorgan- a unit of measurement) for my mother and therefore under the threshold to report.  The match on chromosome 4 is an area of my mother's genome that was not read!

This genetic cousin matches me on one segment of chromosome 3 that I received from my father.  This man also matches my mother and her uterine brother on segments that I did not inherit (instead inheriting that part of my maternal side of chromosome 6 from my maternal grandfather).  This cousin does not match my father's known third cousin, but he does match some of their common Irish matches- which leads me to a specific branch in my father's tree- perhaps where my parents will share ancestors!

This cousin is really interesting because he matches me on a 21 cM segment- larger than what I usually see- but matches neither parent!  The 5 or 6 cM matches can be missed, as the threshold is 5 cM, but a 21 cM segment really should appear in a parent's account.

These strange matches are likely more distant than third cousins.  Our mutual links in our respective family trees are many generations back where the possibilities double every generation, making this a very large puzzle to piece together.

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