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Archiver > GENEALOGY-DNA > 2007-09 > 1188691229


From: "Lawrence Mayka" <>
Subject: Re: [DNA] Abstract: Ancient DNA as a MeanstoInvestigatetheEuropeanNeolithic
Date: Sat, 1 Sep 2007 19:00:29 -0500
In-Reply-To: <009601c7ecdd$02417400$6401a8c0@Richard>


But the immediate topic was the age and origin of the lactase persistence
allele. I have not seen any evidence that the multi-year work of Peltonen
and her colleagues was based on preconceived notions. Indeed, Peltonen's
team does not specifically focus on human prehistory or genetic ancestry at
all, but rather on the genetic origin of metabolic and neuropsychiatric
conditions; so they appear to have no strong vested interest in a particular
date range or geographical origin for the lactase persistence allele.

The most recent paper by this team is

http://www.journals.uchicago.edu/cgi-bin/resolve?id=doi:10.1086/520705

The paper unfortunately costs money, but the best analysis I have seen of it
is this set of articles:

http://scienceblogs.com/gnxp/2007/08/convergent_evolution_of_lactas.php

http://scienceblogs.com/gnxp/2007/08/lactase_persistance_in_eurasia.php

http://www.gnxp.com/blog/2007/08/lactase-persistence-in-eurasia.php


In contrast, the preconceived notion floating around is the genetically
naïve concept that the lactase persistence allele could occur in a given
individual rather recently (since the LGM), then spread all across northern
Europe within a few thousand years, purely by random chance _without_ any
natural selection; and then (miraculously!) prove to be a lifesaver for
populations who have become cattle-dependent. Would this preconceived
notion logically have to extend to the various other world populations in
which other lactase persistence alleles have arisen more recently? In other
words, did this Milk Drinker's Miracle--in which a lactase persistence
allele first spreads across the map purely by chance, and only later begins
to save lives--reoccur multiple times in Africa?

http://www.nature.com/ng/journal/v39/n1/abs/ng1946.html

> [mailto:] On Behalf Of R. Stevens
> My impression is that much of the dating is based on
> preconceived notions.


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