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Archiver > GENEALOGY-DNA > 2001-07 > 0994549556
From:
Subject: Re: [DNA] Projects and Generations
Date: Sat, 7 Jul 2001 19:45:56 EDT
In a message dated 07/06/01 2:30:34 PM Pacific Daylight Time,
writes:
> I have a specific question for everyone as well. It seems to me that if
> three samples share a known (by paper evidence) ancestor some 10 generations
> ago, and one undergoes a mutation, and a branch point occurs later, and then
> there is a reversion mutation, then the parsimony tree will be misleading. I
> know everyone is trying to get at least two samples for every generation. I
> saw in the Mumma tree where samples M21 and M18 represent the product of 5
> branch points over 9 generations (using another equivalent sample as an
> outgroup). So my question is this, which project has in its results the most
>
I'm not clear on what you mean by 5 branch points here. M21 and M18 look like
brothers in the Henry numbering system. Could you lay it out in more detail?
>
> For my part, I suppose I might twist my brother's arm to get tested, but my
> dad had no brothers, so I am already out of luck to determine link
> generation-by-generation in the sense of ruling out reversions. I had
> thought mutations were so rare as to be able to discount the influence of
> possible reversion, but after looking at the Mumma table, I am not so sure.
>
Well, the more the merrier, of course, but I would expect reversions to be
very rare. The overall mutation rate is on the order of 3 per thousand, with
a bias toward increasing the allele length (Kayser,
http://www.journals.uchicago.edu/cgi-bin/resolve?AJHG991495)
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