Archiver > GENEALOGY-DNA > 2005-08 > 1125070465

From: David Faux <>
Subject: Re: [DNA] Newbie's question re a 36/37 match - YCAIIa,b
Date: Fri, 26 Aug 2005 08:34:25 -0700 (PDT)
In-Reply-To: <002901c5aa50$51bc07b0$71509045@Ken1>

Ken et al.:

YCAIIa,b is a fascinating marker. There were two clearly R1a1-M17 haplotypes in the skeletal material in the 3000 year old necropolis in Eigen Gol, Mongolia. Each has values at this marker of 19,23 which is almost universal to this day in the "R1a world" - with the unusual exception of 40% of R1a Scandinavians who have a 19,21 motif. I am consumed with the desire to find out whether this was a local mutation, or whether, as I have hypothesized (19,21 has been seen in India and Arabia), that it emerged in one of the Central Asian tribes before the latter moved to Scandinavia with haplogroups Q and K. A very informative marker indeed.

David Faux.

Ken Nordtvedt <> wrote:
Whether the others get 18 or 19 at YCAIIa should make a lot of difference in
the further detective work. You start with the understanding that a
mutation within a "family" from 18 to 19 or from 19 to 18 will most probably
occur just once in the last 10 generations or so. This eliminates many of
the possible tree arrangements you could imagine between these 4 peoples'
ancestral lines (i.e., you can downgrade the possible trees which have
YCAIIa mutating twice). Then you can take into account that the 18 is much,
much more rare in the population of I1a haplotypes taken as a whole. If you
end up with alternative trees which your paper detective work led you to,
then the one with 19 as the ancestral value would probably be more likely.

The genetic input which tilts the odds must of course be folded into the
paper evidence you accumulate, and it could influence which directions you
pursue in the paper chase.


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