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Archiver > GENEALOGY-DNA > 2011-09 > 1315848046


From: Mike W <>
Subject: Re: [DNA] Interclade: G=11.5 SigmaG=7.5
Date: Mon, 12 Sep 2011 12:20:46 -0500
References: <CAEfV5jA88UvExh8Jz_jJiS19jqp-2jutzHAXDGo+Pr--g_Uz9A@mail.gmail.com><BE04498836564CAD9858C5C6B2A6356E@kenPC><A50FBB589C5A418FA4181F87A3595BF5@kenPC><AFFC72827C6F4308A6346EC70B83D8D6@kenPC>
In-Reply-To: <AFFC72827C6F4308A6346EC70B83D8D6@kenPC>


Ken, you may have seen this, but in "The peopling of Europe and the
cautionary tale of Y chromosome lineage R-M269," Busby et al makes a couple
of assessments related to using Y DNA STRs as follows:

"Contrary to common belief, estimates of ASD, and therefore T, vary widely
when different subsets of STRs are used with the same sample."

"When we manipulated our choice of STR marker based on u(R)/2m (a surrogate
for D; table 1), we found that different sets of STRs gave different values
for T. It is clear, then, that coalescence estimates explicitly depend on
the STRs that one uses."

Your assessments indicate adding more STRs to the analysis is helpful, but I
know that it is common to throw out multi-copy STRs in TMRCA estimates that
are of a deep ancestral nature. Do you agree that additional STRs should be
filtered out, as Busby did? or where and how do we draw a line as to
determining what STRs to use in TMRCA estimates?

Regards, Mike W

---------- Forwarded message ---------- From: Kenneth Nordtvedt <
>

[[ There is one way getting "enough data" can drive down the sigma
indefinately --- incorporating more STRs into your haplotypes. That is
because each STR is an independent experiment which has run through the same
tree back to its root that you are trying to time extimate. ..... KN ]]

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