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Archiver > GENEALOGY-DNA > 2009-12 > 1260384641


From: David Faux <>
Subject: Re: [DNA] R-U152 and R-L21 on the European Continent
Date: Wed, 9 Dec 2009 10:50:41 -0800
References: <mailman.279.1260259242.26095.genealogy-dna@rootsweb.com><A93225B377724B83BF5250F368878955@anatoldesktop><ea3bd9560912080855u5f4216a1g4d0b6a16d543dae1@mail.gmail.com><REME20091209002724@alum.mit.edu><ea3bd9560912082206r79afe90ubf5cf4f7ca9774fb@mail.gmail.com><REME20091209015633@alum.mit.edu>
In-Reply-To: <REME20091209015633@alum.mit.edu>


In my view a one word answer is severely simplifying what is a very complex
and intricate matter. An organism survives by seeking homeostasis as
exemplified by hormonally regulated eating behavior guided in part by gut
satiety hormones. However when the environment poses challenges only those
organisms which have "eccentric" mechanisms to assert balance may survive or
thrive when a calamity such as a years long volcanic dust cloud screening
the solar radiation. This may favor those in a group who by chance can
attain a homeostatic balance by eating fewer times a week due to slightly
lower core temperatures and slower metabolism. When the environment changes
again, those in a more advantageous position to exploit the new (or
previous) conditions will be selected. In the meanwhile what has been
happening to mutation rates and the processes (in the plural) which at least
govern the major parameters. The truth is we don't know. I am not sure why
you would assume that everything would be static. However in my opinion it
is a bit naieve to expect that no change will be the order of the day
throughout a lengthy period where the only constancy is change. What may be
relatively constant is the rolling average of the STR mutation rate over the
interval of time since the ancestors of pan and homo went their separate
ways. Possible. However, just as with the charts for climate change, the
mutation rate over 7 million years may have fluctuated wildly at certain
points. Again I get back to my original statement that we cannot know by
any direct means, or any non controversial indirect means, what the mutation
rate of Y-STRs was in the Bronze Age let alone the Mesolithic.

David K. Faux.

On Tue, Dec 8, 2009 at 10:56 PM, John Chandler
<>wrote:

> David wrote:
> > There are cataclysmic periods, and periods of relative
> > stability. Only a statistician would dig in their heels and maintain
> that a
> > biological system that is constantly evolving would somehow be
> > "conservative" in one area
>
> I have just one word to say to you: homeostasis.
>
> John Chandler
>
>


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