Following on from my last post, just a quick update to mention how close I am to finding my Grandfather’s biological father.
I recently checked the relative finder feature on 23andme.com to find I had a new match… not just any new match, the closest one in the entire list of related matches! I think I actually stopped breathing in the moment when I saw it!
A potential 3rd to 4th cousin, he shares 0.59% DNA with my Grandfather on 3 segments. My previous closest match was 0.37% on 2 segments. 0.59% doesn’t sound like much but to put it into perspective, you lose roughly 50% of DNA for each generation you go back, while starting off with the 50% you receive from each parent. So it quickly diminishes. When looking at other relatives you then have to halve it again. It’s confusing but this table from FamilyTreeDNA shows how it works.