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Archiver > GENEALOGY-DNA > 2006-11 > 1162650684


From: "Alfred A. Aburto Jr." <>
Subject: Re: [DNA] Molecular clocks: when times are a-changin'
Date: Sat, 04 Nov 2006 06:31:24 -0800
References: <000201c6ff94$7cbe8060$4001a8c0@BigMem2><REME20061103235815@alum.mit.edu>
In-Reply-To: <REME20061103235815@alum.mit.edu>


> John Chandler [speaking to John McEwan] wrote:

>Yes, we have been through this before. You were unpersuasive then,
>and that hasn't changed. You must bear in mind that the context
>here is the genealogical time scale, or at the very most the ages
>of some of the haplogroups that people here like to talk about when
>they want a break from genealogy. In other words, we are talking
>about at most 1000 generations, which translates to an expected
>quota of about two mutations per locus on all of the loci used in
>the academic research on populations. This quota is entirely within
>the actually observed human variation of these loci, and so it is
>absurd to invoke natural selection as a factor in the effective
>mutation rate.
>
>

In the paper by Ho & Larson (2006), referenced initially in this
discussion, the genealogical time scale is set as < than 1 million years
ago. If you look at his curve (called a "hockey stick" curve by some I
think) in Figure 1 you'll see that the mutation rate, in this theory, is
_rapidly_ changing at ages _less_ than about 1-2 million years ago,
between 0 and ~1 million years ago. I think this theory, not yet
completely "proven" or "accepted", is a reasonable explanation why there
is such a wide disparity in observed mutation rates ...
Al

[snip, snip]

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