My Great-Aunt Ree Albea Wingard's DNA test results started coming in tonight. I purchased a test for her from 23andMe back in August and it took 28 days for her results to come back (plus three weeks lost in the mail). So what have I learned?
First, and most obviously, I learned that she is indeed my Great-Aunt. I wasn't expecting otherwise, but it's nice to prove our relationship scientifically. And then by deduction, my grandfather is my grandfather - any DNA match between my great-aunt and myself is a reflection of DNA I inherited from my mom, who inherited it from her dad. And really, that's partly why I tested my Great-Aunt: she is standing in for my deceased paternal grandfather.
Here's a visual of the DNA I share with my Great-Aunt Ree (right), as well as the DNA she shares with my mom (left).
You can see that my mom shares more of her DNA with Aunt Ree than I do. On top of that, there's a large portion of Aunt Ree's DNA that my mom and I do not share. This is where testing her DNA comes in handy. In those portions of her DNA I will find cousins that I would not otherwise find. Also, her DNA is yet another generation further back in time, another generation closer to a common ancestor we share with a DNA match.
For example, look at one of my matches. This is a match with Mr Rush, my 3rd cousin twice removed. Our most recent common ancestors are John P Quattlebaum and Permelia Langley, my 4x Great Grandparents. Mr Rush is then Aunt Ree's third cousin. Here's the visual, with Aunt Ree and Mr Rush on the left and my comparison with Mr Rush on the right:
You can see that Aunt Ree and Mr Rush share DNA segments on two additional chromosomes. My mom didn't share these segments. Now imagine that Mr Rush and I didn't share that segment on Chromosome 10. I'd be able to identify him through his match with Aunt Ree on Chromosomes 1 and 3.
I'm still waiting for Aunt Ree's relative finder (cousins test) results. Until then, I can compare her to my existing matches. If they match her, then I know I have narrowed our match down to my paternal grandfather's side of the family. If you have tested with 23andMe keep a lookout for my aunt in your matches!