Tuesday, October 14, 2014
AncestryDNA Phasing FFFFF..ail!
I listened to the explanation of the AncestryDNA phasing process via a video from i4GG. It seemed like a good idea. Now I'm thinking it's not really a good idea; especially when there is no way to see the segments you share with matches. I don't want phasing unless I can see the segments!
I found several new Ancestry matches at GEDmatch. I was shocked to find that one very low confidence match shared a 22.4 cM segment with me. I later checked to see if he matched my Mom and he shared the same 22.4 cM segment with her. This was a phasing fail because obviously I received this segment from my Mom. This was judged to be a "very" low confidence match for both of us. I can't find a common ancestor at this point. It may be that this person matches us many generations ago. It could be what CeCe Moore called a "sticky segment" which remains intact for hundreds of years? I want to see matches like these ranked higher? When AncestryDNA prunes our matches I'm hoping they don't eliminate matches with shared segments 10 cMs or larger?
We need to know more about the segments we share with matches. There is no way to get around 10,000 matches to compare at GEDmatch. If everyone at AncestryDNA uploaded to GEDmatch the servers would probably crash and burn, so that's not an option.
PS My Cousin Susan also shares the same 22.4 cM segment with the very same match (thanks Nan!)