I’ve been trying to find out the identity of my grandfather for quite some time and recently, new DNA matches have meant it easier for me to narrow it down. I have 3 matches that are all descendants of one particular relationship (Bridges/Nisbet) who were their great grandparents and I am roughly 2nd cousin cM to all of them, so looking at their family tree, there are possibly around 3 people who would have been old enough to be my grandfather at the time he was born.
A question was asked of me whether I had considered the father could be a descendant of a sibling to GGrandpa Bridges, but that was refuted as I have Nisbet matches too. Pretty solid so far....
Until I found out that the sister of Bridges married the brother of Nisbet and had their own children etc etc. As there are now two bunches of Bridges/Nisbet DNA, I suppose it does make it possible that I am descendant of this other relationship.
How could the fact there are double cousins get in the way of what I already have done?
Is there a way to find out whether I am a double cousin to these matches or a true cousin?
If I was a double 3rd cousin instead of a true 2nd cousin, my dna matches with these three would be weaker than what they are ( roughly 300cm each)?