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Archiver > GENEALOGY-DNA > 2010-02 > 1267424082


From: "Tim Janzen" <>
Subject: Re: [DNA] : low variance MRCA dates for P310cladesinItalyandSEEurope
Date: Sun, 28 Feb 2010 22:14:42 -0800
In-Reply-To: <003501cab8f8$8f0a0840$5e82af48@Ken1>


Dear Ken,
I agree. That was my point. Sometimes we need to cull out
haplotypes from close relatives so as to avoid skewing the intraclade
coalescence age estimates to be lower than they would be if the haplotypes
from close relatives were included in the dataset. However, even after
removing the extra haplotypes from multi-members of surname projects or
haplogroup projects you may still be left with a large number of haplotypes.
If the number of haplotypes is too large (over 100 or so) you typically
start to see intraclade coalescence age estimates decline the more
haplotypes that are included in the dataset.
Sincerely,
Tim

-----Original Message-----
From:
[mailto:] On Behalf Of Ken Nordtvedt
Sent: Sunday, February 28, 2010 8:35 PM
To:
Subject: Re: [DNA] : low variance MRCA dates for
P310cladesinItalyandSEEurope

It never pays to stack the samples with anything --- close relatives or
purported outliers. Any bias in the sample selection will probably produce
a bias in the coalescence age.

I go out of the way to not take multi-members of surname projects, because
the nature of such data collections is stacked in the direction of close
relatives (late separating branches).



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