MRCA - why sometimes one and sometimes a couple

[familydar]

By couple I mean mother and father, not two unrelated people which would be a double relationship.

A*y hints for my dna kit can suggest a solitary mrca even when both halves of the couple are present in both trees.  Generally the predicted relationship is at least two degrees more distant than the paper trail suggests, so perhaps the real mrca is a grandparent of the suggested person, and further back than our trees go.  If indeed the case, then this implies that one or both of us have an error in our trees.

I'm guessing that the algorithm used is managing to rule out the spouse, but how, when there are no matches in common with the one it has picked?


Jane :-)

[hurworth]

Are the details (DOB and place) for these people exactly the same on both trees?

I've noticed Ancestry hasn't picked up on several MRCAs and I'm not sure why.

[familydar]

Yes exact matching on date and very specific location.