understanding dna results

[redjed1]

Hi,

I sent off a sample of dna for a 12 point check, to compare against other related surnames. I have now been told that I have a 100% match with someone.

Does this mean that somewhere in the past we definitely share a male ancestor?

Am I right in saying that anything less than a 100% match means that the two people have no common male ancestors?

John

[john franks]

Hi John,

All men have a common ancestor at some time in the past - for any two individuals it may be in the very distant past. But your exact match for 12 markers narrows it down quite a bit.

According to FamilyTreeDNA, who did my tests, this  means that, for example, there is a 55% chance that you have a common ancestor eight generations back. As you go further back in time the probability increases so at sixteen generations the chance is 80%, for example.

The sort of result you have got may give you an idea of where to look to get further back in your family history.

John

[redjed1]

Hi John

Thanks for that.

My match and I have (almost) the same surname (Duvall / DuVall).
I can go back 8 generations to about 1720. My "match" has no common ancestor in those 8 generations, so our common ancestor must be 9-12 generations back, as that's when our original family apparently sailed to america.

John