DNA matches Q
 

Previously I said on another thread I did wonder if my great-grandfather was really my great-grandfather or whether he was duped into marrying his housekeeper because she was expecting a baby (my gran).

Looking at my DNA matches I see Ancestry has picked up that I am 'extremely' likely to be a second cousin to an individual (Shared DNA: 246cM across 14 segments). This person's grandmother is sister to my grandmother and both those woman are children of the housekeeper and maybe of my supposed great-grandfather.

My Q is, if the two grandmothers/sisters had different fathers would I be able to tell by the degree of DNA match, or are there too many variables to make any assumptions?

Best mate's closest is third - fourth cousin: Shared DNA: 191 cM across 13 segments.

Slightly further down the pecking order, a third cousin (tho' possibly removed) ranks lower than a fourth cousin.

I suspect that the balance of probability is that you share a great grandfather. Do you have matches with anyone men of his surname? Or is it Smith?

Have you looked at the shared matches, Merry? Maybe some of them will be on your great-grandfather's side to confirm him as your blood ancestor?

I have looked at the shared matches, but this cousin and one other person are the only two I have any idea about. This one I have known my whole life and the other one is a fourth cousin match with my dad's surname (so other side of my tree), but I have no idea who he is (no tree uploaded). All the rest of the names mean nothing at all at the moment.

I have been working backwards from the most obscure 5-8 cousin matches to build up ancestor profiles. I do not understand why A matches B and C, B matches A and C, but C only matches A.

Making notes on the matches does ultimately build up profiles. But it has taken up my entire life for two months, and I have only eliminated 11,500 poor matches so far!

lol Phoenix, I think I will have to wait until January!