Are marking both person from the CA couple as "confirmed with DNA"?

+6 votes
100 views
Other than what most people belief the CA (common ancestor) is actually not identifiable as a single person, even though only one person gave the ancestral segment(s) down to his/her descendants (for autosomal DNA tests).

That leaves the challenge that IMO both parents of the CA couple have to be marked "confirmed with DNA" even though we know that only one of them is actually proven by DNA, the other didn't give any DNA downwards to these descendants (that person can obviously give it's DNA down to other descendants which can triangulate on different segments).

Is this common practice that you also do? Are you always naming both ancestors (unless they become MRCA = most recent common ancestors -> then the CA above them is still a couple)?
in The Tree House by Andreas West G2G6 Mach 5 (53.9k points)
The CA will become MRCA when a CA further up is identified. Then there is enough evidence which of the two parents gave down the ancestral segment.

1 Answer

+1 vote
Hello Andreas,

When ancestral lines are confirmed using a Triangulated Group (TG) then the ancestral couple is not included.  Just the lines up to them.  When using the total amount of shared autosomal DNA for third cousins or closer, then both father and mother of the ancestral couple can be marked as "Confirmed with DNA".   

When using X-DNA matching and the confirmation is through a son of the shared ancestral couple then you know that X-DNA segment came from the mother of that ancestral couple and she can be "Confirmed with DNA".  If the X-DNA matching cousins descend from two daughters of the ancestral couple then the you don't know who contributed the shared segment and so the ancestral couple is not included.  Just the lines up to them.
by Peter Roberts G2G6 Pilot (523k points)
edited by Peter Roberts
Peter,

I don't fully get your post as it seems to contradict itself with your addition of "total amount of shared DNA for third cousins or closer".

Here's the relationship path to the current CA: http://www.wikitree.com/index.php?title=Special:Relationship&action=calculate&person1_name=Mocsny-1&person2_name=Oster-216

As per my explanations it's unknown if Joannes Kastor Adams or Margaretha Jax has given the ancestral segment to their descendants. What should the relationship be of their two children which form the path down in the relationship finder report?

Both people share 83.7cM and are third cousins once removed.

I assume with "lines to them" we agree the current form is correct, right? Like I wrote, I don't get the second part about why the parents of that ancestral couple should have the same "confirmed by DNA" as only 1 out of the 4 lines is indeed correct (but currently we don't know which one).

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