Reliability of Cousin/MRCA/GEN calcs at FTDNA and GEDmatch

Question

My brother and I (Toemmes-1 and Toemmes-4) match Weathford-199 on chromo 12 at 14+ cM.  Additionally I match her on 3 and 8 at 9.8 and 8.3 cMs respectively,  So I consider ti a fairly good match.

FTDNA predicts we at 5+ cousins.   GEDmatch predicts we are 4.5+/- MRCA/Gend so I consider them consistent.

However, "paper" connection show 7-1 cousin (FTM) and 8 cousin (WikiTree) connection and while not a maternal or X connection this is along a great part of my suspect maternal line.

So, to me, it seems that there has to be a closer connection as yet undiscovered.

What say you?

Thanks,

Pete

Answer 1

I believe the close prediction is due to endogamy in the Bahamas and/or a genealogical error.  There could also be a non-paternity event and/or a not yet discovered closer connection.

You both have Bethell and Thompson ancestry from the Bahamas.  All the Bethel/ls of European descent from the Bahamas who have been Y-DNA tested belong to the same direct paternal line.  Same for the Thompsons.

It is my experience that if two people do not have a genealogical error, or a non-paternity event within seven or eight generations or do not come from an endogamous population then the Family Finder and GEDmatch relationship predications are usually very accurate.

Your mtDNA mismatch in your direct maternal line strongly suggests there is a genealogical error in that line.

Sincerely, Peter

Comments

I do have  Thompson  in my line not sure about bethals iwill have to seach that name