GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2008-12 > 1229082416


From: Vincent Vizachero <>
Subject: Re: [DNA] Why Western M269 can't be accurately aged
Date: Fri, 12 Dec 2008 06:46:56 -0500
References: <917892.81379.qm@web81104.mail.mud.yahoo.com>
In-Reply-To: <917892.81379.qm@web81104.mail.mud.yahoo.com>


This is the Zhivotovsky study that has been dissected ad nauseam
before. It is an interesting paper, but only somewhat related to the
topic of this thread.

Most importantly, there are many conditions in the paper that may or
may not apply to R-M269 related to effective population size and
population growth rates. Also, most of the problems the paper is
concerned with are relevant to intraclade variance estimation but not
to interclade variance estimation. The authors also conflate,
whether intentionally or unintentionally, the concepts of founder and
MRCA - in fact, they avoid the term MRCA altogether even though that
is the only thing that CAN be directly estimated using modern genetic
data.

But whether the MRCA of R-M269 can be "accurately aged" depends
largely on what you mean by "accurately". Also, the age of
"western" R-M269 is inextricably tied up in a larger discussion about
all of R-M269 and also other upstream R1b nodes.

I think the question that still haunts most people is whether or not R-
M269 could have existed during the LGM in a Franco-Cantabrian refugium
and expanded into Europe from there afterwards. Without need for
dismissing Zhivotovsky's arguments, which are - at least as presented
in this paper - generally reasonable, we can establish that the
answer to the question above is "not". That answer draws in part on
TMRCA estimation, but also on other evidence.

Dienekes undertook a very thorough (and quite smart) analysis of
topics related to the Zhivotovsky paper last summer.

http://dienekes.blogspot.com/2008/07/how-y-str-variance-accumulates-comment.html

Vince

On Dec 11, 2008, at 11:41 PM, Gary Felix wrote:

> They also make the point that modern day germ line mutation rates
> can't be compared to evolutionary mutation rates. Consider that
> rates today are computed from expanding populations with some degree
> of consistency. Now consider that you are western M269 and computing
> rates 10K years ago. Your ancestors would have been the survivors
> that outnumbered the variants bottleneck after bottleneck
> (preserving modality).


This thread: