GENEALOGY-DNA-L ArchivesArchiver > GENEALOGY-DNA > 2006-10 > 1161767782
From: "Alister John Marsh" <>
Subject: Re: [DNA] 12 Marker Matches Within Surname Groups..
Date: Wed, 25 Oct 2006 22:16:22 +1300
"I have voiced my opinion before that 12 markers is pretty much
useless unless your intent is to prove two people are NOT
related. Even with the same surname."
I think a lot depends on context. Particularly if some very rare off modal
marker scores are involved. I once found a partial haplotype on Sorenson
with only 2 markers to compare to FTDNA markers. I confidently (..rashly??)
matched that to a family, based only on those two markers, as the markers
just happened to be rare off modal scores. When a full set of markers were
eventually obtained, the match went from 2/2 to 25/26. Perhaps I was just
lucky that time. Clearly 2 markers are better than none, 12 are better than
2, and 67 better than 12.
I had a case of 10/12, which included 4 mutation steps. I predicted that a
relationship was possible, as geographic location matched, a rare marker
score matched, and a recLOH looked possible on DYS385. Markers 13-37 when
they were later obtained only had 1 mutation step, on the fastest mutating
marker. Bridging haplotypes were also later found which made relationship
seem more credible.
I have a case of a 12/12 match of a surname variant, which I am almost sure
means no match. The geography feels wrong, and the markers are near modal.
I have a case of an 11/12 match, with paper trail connection, which I wonder
about. The mismatch is on the distinctive family marker, and other markers
are near modal.
I don't very often think in terms of 10/12, or 12/12. or "4 mutations on 12
markers". I am looking for matches on distinctive, off modal, slow markers,
and I add that to the surname, geographic location, and paper trail context,
to see what sort of "gut feeling" I get. Are "gut feelings" admissible
Perhaps about 10%+ of my project participants have something sufficiently
distinctive in the first 12 markers, to make a 12/12 match look interesting.
For the others, 12/12 would be to various degrees into a "zone of
|Re: [DNA] 12 Marker Matches Within Surname Groups.. by "Alister John Marsh" <>|