On Sep 7, 2020, at 5:57 PM, Herbert Lazerow <lazer@...> wrote:

I have a known third cousin once removed who has tested on Ancestrydna and who matches me at 41, longest string 19. That person's brother, presumably also a third cousin once removed, matches me at only 13 cMs. Removing all matches below 20 cMs deprives me of knowing how long the longest string with that person might be.

Similarly, I have two known third cousins, one 3C1R and one half-1C2R under 20 cM.

More importantly though, I have a 14 cM match that led me to a cousin from a branch whose father had changed his last name to a very common one that made him impossible to find.

A Y-DNA test with the cousin -- the only surviving direct-paternal male descendant in his branch -- showed that he and I shared a common paternal ancestor and that our two branches were definitely related.

Without that 14 cM match I would never have been able to find the cousin to take the test.

David Brostoff