Sunday, August 12, 2012

DNA Testing: Grandfather's First Cousin

Katherine Dunn (1865-1944)
Wife of William Walling Winterton
I think I inherited her lower lip.  Maybe the nose.
Another DNA kit is on the way to my paternal grandfather's first cousin.  23andMe had a sale, so it seemed like a good time to test another relative.  The common ancestors of this cousin and my father (and me) were William Walling Winterton (1863-1932) and Katherine Dunn (1865-1944).  They lived in Monmouth County, New Jersey and are buried at Green Grove Cemetery in Keyport.

If we tested both cousins, they would share about 12.5% of their DNA.  We can't test my grandfather because he is deceased, but we do have the results of my father.  My father should share approximately half the DNA that his father would have shared with this first cousin, or 6.25%.  As the next generation, I should share about 3.125% with this first cousin, twice removed.

(Keep these percentages in mind as you flashback one year ago to my 5% match who is still silent.  This person could be as close as a cousin to one of my grandparents.  This is so strange because I *think* I am aware of everyone researching my closest lines and they deny DNA testing.)

DNA inheritance can be rather random, so it will be interesting to see the exact percentages shared.  To view charts comparing DNA of cousins, please view this post by Andrea Badger.

The purpose of testing this latest cousin is to triangulate matches.  The DNA testing companies provide you a bunch of "genetic cousins."  You search your ancestral tree and the tree of your genetic match to locate a common ancestor, or source of the shared genetic material that survived all these generations.  This sounds easy, but it is not.  Once the results of this cousin are complete, we will identify genetic matches in common.  This will point us to a specific branch in my father's tree:  his father's mother's branch.