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Subject: Re: [DNA] Times of Haplogroup "Divergence" vs. Population "Divergence"?
Date: Tue, 1 Jun 2004 21:08:19 -0400 (EDT)
References: <20040601202149.29616.qmail@web11407.mail.yahoo.com> <000d01c4481b\$7d265ec0\$48e289d1@Ken1>

Ken wrote:
> In a recent paper on the European "I" haplogroup and its subclades,
> estimates were made of "divergence times" for various pairs of the subclades
> and "divergence times" for the populations of the subclades.
>
> Could some one explain in words which are solid but not so professional what
> is meant for the divergence time of a subclade's population?

I think that's just the same as the "convergent time" looked at in the
opposite direction. In other words, it's the average variance of the
tested loci within that population, divided by the average mutation
rate. In short, it's the estimated age of the subclade.

The divergence time for a pair of subclades is a little slipperier
because you can think of a subclade as an "individual" with the
average statistics of its members or as one part of a combined
population consisting of the members of two subclades.

> present in the paper because "expansion" is used interchangeably at one
> point. One can imagine a subclade coming into existence in some small tribe
> somewhere; the population of the subclade remains modest for thousands of
> years, and then for some reason there is an explosion of territory and
> population of that subclade at this later time. How is the divergence or
> expansion time of a subclade's population estimated?

In order to detect a recent, rapid expansion, you must take
geographically separated samples and compare the variance within each
group to the overall variance.

John Chandler