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Archiver > GENEALOGY-DNA > 2005-08 > 1123112150


From: "Earl Beaty" <>
Subject: SNP mutation rates
Date: Wed, 3 Aug 2005 17:37:59 -0600
References: <IGEOKAGLHNEKPCKPADIGOEIKKEAA.bbailey.lowedna@baileyconnection.com> <REME20050803190044@alum.mit.edu>


A superficial observation:
We have much talk on this list indicating that a person's haplogroup is
determined by one SNP. For instance P25+ means R1b (or R1b1 depending on the
standard). But nobody is concerned with the possibility that a man might be
in two haplogroups.

The answer to that puzzle is easy. P25+ is not just a single marker because
experience his shown that it implies other mutations and it is the whole set
which defines R1b. The mutation rate is alleged to be very low and that
explains why we don't find P25+ showing up in members of haplogroup J or
E3b. But all those R1b guys have had many mutations since Y-Adam and that
seems inconsistent with the very low mutation rate.

A very low mutation rate would normally mean the many men would have had no
mutations at all since Y-Adam. The 2005 Chart doesn't even have a name for
the highest node. The highest named node is 'A', and I don't remember that
haplogroup even being mentioned. It seems to be an assumption that all
ancestral lines from Y-Adam to the present have suffered several mutations.

I might be able to construct a reasonable explanation for the above, but my
version is not really believable. Can someone here make a explanation which
could be given a G rating?

--Earl Beaty


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