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Archiver > GENEALOGY-DNA > 2010-02 > 1267408919


From: "Ken Nordtvedt" <>
Subject: Re: [DNA] : low variance MRCA dates for P310cladesinItalyandSEEurope
Date: Sun, 28 Feb 2010 19:01:59 -0700
References: <201003010133.o211Xc5t015627@mail.rootsweb.com>


----- Original Message -----
From: "Tim Janzen" <>

because we don't know the overall tree structure. This
> problem won't be completely revolved until we have widespread complete Y
> chromosome sequencing available so that we can determine what the tree
> structure is using all of the SNPs on the Y chromosome for the various
> branches.

[[Once you have this total Y SNP information you will probably have little
reason to do the STR-based age estimates KN]]


> Another issue is how many haplotypes is optimal for intraclade
> coalescence age estimates. From having done quite a few intraclade
> coalescence age estimates previously I have noted a tendency for
> intraclade
> coalescence age estimates to start declining once you reach 50 or so
> haplotypes.

[[ So what's the problem with declining coalescence age estimates with more
haplotypes? Since the relationship between coalescence age and TMRCA is
rather fuzzy because of not knowing the tree structure, what difference does
it make? Your declining coalescence age is probably approaching the same
for the whole clade tree in any case. What's an "optimal" estimate of
coalescence age? KN]]



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