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Archiver > GENEALOGY-DNA > 2007-02 > 1171802889


From: James Heald <>
Subject: Re: [DNA] There is no WAMH (R1b modal) cluster
Date: Sun, 18 Feb 2007 12:48:09 +0000


Jim T <> wrote:

> There is no WAMH cluster, i.e., there is no R1b modal cluster.
> Compare the results of these two Ysearch queries:
>
> http://tinyurl.com/ywmo2n
> http://tinyurl.com/2c9h3t
>
> They both specify 67 markers with maximum genetic distance = 5.
> The first specifies the R1b modals. The second specifies the
> R1b1c7 modals. The R1b modal query finds just 1 man. The
> R1b1c7 query finds 31 matches. If you increase maximum genetic
> distance to 7, the R1b query finds 5 men, while the R1b1c7 query
> finds 56. It seems that R1b1c7 is a real cluster and that the
> WAMH isn't.

> I used to think that the WAMH was essentially identical to the
> haplotype of the MRCA of R1b1c. I’m not so sure about that
> anymore, given the structure of R1b. I still think that it is
> probably true that the modal of the slower markers is their
> ancestral value. I doubt whether we can reliably deduce the
> ancestral values of the faster markers with the data that we
> have at the moment.

WAMH is the average of lots of clusters, and is not a bad for being
(very close) to the haplotype of their common ancestor.

But the most recent ancestors for the clusters are a lot more recent
than the WAMH ancestor, so you would expect quite a genetic distance to
build up in that time.

In fact, given the lengths of time we're talking about, the probability
distribution of that genetic distance (whatever the metrix we choose)
*should* be quite strongly peaked away from zero.

Given the time interval, it should *not* be a surprise to find very few
modern individuals close to the ancestral haplotype.

All best,

James.


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