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Archiver > GENEALOGY-DNA > 2002-09 > 1031084640


From: "John F. Chandler" <>
Subject: Re: [DNA] Two Paleolithic Y groups in Europe Before the Third/Neolithic
Date: Tue, 3 Sep 2002 16:24 EDT
In-Reply-To: philr@stanford.edu message <5.1.0.14.2.20020903095814.01acaa10@philr.pobox.stanford.edu> of Tue, 3 Sep 2002 11:17:05 -0600


Phil wrote:
> The following statement puzzled me. I understand that the Y chromosome is
> found in nearly all mammals so must be much older than 60,000 years.

Yes, that's true. However, the statement refers just to the level of
diversity in the present-day human population. In other words, if you
take into account the mutation rates (known or assumed) for the Y
chromosome, all presently occurring samples could be explained by random
mutation from a single individual about 60,000 years ago. This does NOT
imply that the entire human population 60,000 years ago had just one
Y haplotype -- in fact, it seems likely that the population at that
time was just as diverse as it is now. In the meantime, there have
been floods, fires, earthquakes, famines, wars, and plagues of all
kinds. Every disaster results in the loss of some diversity. The
60,000-year figure simply represents the relative importance of
disasters and mutations in the human male population averaged over
recent time. The same can be said for the 170,000-year figure for
mtDNA and the female population.

John Chandler

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