Archiver > GENEALOGY-DNA > 2006-10 > 1161792061

From: OrinWells <>
Subject: Re: [DNA] 12 Marker Matches Within Surname Groups..
Date: Wed, 25 Oct 2006 09:01:01 -0700
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In-Reply-To: <>

I will stand by my statement. I will not say that it is not possible
for a 12/12 marker match to be valid, but the frequency of such
matches with non-related individuals is just too high to be a
reliable indication of a relationship. In the two cases where the 26
marker matches (one was a perfect match and one was off by a single
marker) they had perfect 12/12. In each case the surname was a
match and each pair of families were from the same geographical area
and both pairs matched on the haplogroup. But we couldn't find the
paper trails, just circumstantial evidence. It was only at 43
markers that it became clear there were no connections.

I also do not have our participants test at 12 markers, ever. Partly
because Relative Genetics never offered a 12 marker test. Perhaps if
they had done so they might have as many tested customers as Family
Tree DNA by now. They have introduced an 18 marker test that is
competitive in price with the 12 marker test. I currently encourage
our participants to go directly to the 43 marker test unless we are
confident we know where their test is going to lead and we are only
trying to confirm it. This is currently working well for us because
we have been able to utilize the Sorenson discount coupons that bring
the 43 marker test down to an affordable price for the participants.

At 02:16 AM 10/25/2006, Alister John Marsh wrote:
>You said...
>"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
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Orin R. Wells
Wells Family Research Association
P. O. Box 5427
Kent, Washington 98064-5427
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