Hi everyone, there's something I don't understand about the DNA confirmation rules so would like to have some discussion.
In the [[Help:Triangulation]] page. section "Do you include the MRCA?", it explicitly says that if the documented MRCA is a couple, then not to mark either of the MRCA as "Confirmed with DNA". Only the legs should be marked.
This seems sensible to me, as the match only proves that at least one of the two in the couple are a common ancestor of the people in the legs.
However in the rules for one-to-one confirmation, [[Help:DNA_Confirmation#Which_Relationships_to_Mark_as_Confirmed]] it says that both of the MRCA couple should be marked.
I don't see how this is any different, and why the same rationale doesn't apply. The evidence only tells us that at least one of the two in the couple is a common ancestor, especially if it was a low cM match
For example, using the names from the diagram on the Confirmation page: supposing Helen's father is actually a David , and then Bob shows up with a DNA match to Helen and a bunch of strong unknown matches, the fact that Jason was marked as DNA Confirmed to be Helen's father is going to interfere with his search .
It doesn't seem to make sense that even though a one-to-one match is less evidence than a triangulated match, it requires adding greater DNA confirmation markers.
Context - I was asked to mark the DNA confirmation of both of the MRCA couple for a 2C1R with 56cM match (the expected value for full 2C1R from DNApainter is 122cM), I have complied but I feel dishonest in doing so. I also have another 2C1R with a 37cM match where the same question would arise.