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Archiver > GENEALOGY-DNA > 2007-06 > 1182476913


From: (John Chandler)
Subject: Re: [DNA] TMRCA Corrections
Date: Thu, 21 Jun 2007 21:48:33 -0400 (EDT)
References: <004101c7b33f$d2296bf0$6400a8c0@Ken1><REME20070620221136@alum.mit.edu><012b01c7b3ba$b580baf0$6400a8c0@Ken1><REME20070621172446@alum.mit.edu><003001c7b450$d63d6680$6400a8c0@Ken1><REME20070621190128@alum.mit.edu> <007a01c7b466$526f7ad0$6400a8c0@Ken1>
In-Reply-To: <007a01c7b466$526f7ad0$6400a8c0@Ken1> (knordtvedt@bresnan.net)


Ken wrote:
> One could take an empirical plunge into the problem. Just look at the
> distributions of the marker repeats we see today and forget about the early
> days of the clade and how that era may be responsible for distorting the
> distributions. From that distribution we can directly calculate the rates
> of change going on in recent generations where it matters.

Indeed, that's roughly what has to be done anyhow, since the age of
the clade has to be estimated from this sort of information. Close to
the mode, I think you're right that the distortions will have relaxed
toward a shape matching a somewhat younger effective age. Out on the
fringes, however, the extinction effect should still be retarding the
spread. Maybe that doesn't matter much, though, since such haplogtypes
are necessarily very rare.

John Chandler


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