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Archiver > GENEALOGY-DNA > 2007-03 > 1172877691


From: Alan R <>
Subject: Re: [DNA] Lactose tolerance evolved recently
Date: Fri, 2 Mar 2007 23:21:31 +0000 (GMT)


My hunch was actually that there was always a (very
low) proportion of lactose tolerant individuals
possibly fairly evenly spread through the Mesolithic
population of Europe. When dairying came, it gave a
huge advantage to those would had natural tolerance in
areas where dairying was by far the best agricultural
option. What I envisaged was thousands of local
expansions stemming from advantaged individuals NOT
expansion of lactose tolerance through long distance
movement of expanding/ invading lactose tolerant
populations.

One of the spin-articles regarding the new genetic
testing of central European Neolithic human bones
implies that all the lactose tolerant people in
Northern Europe today are descended from one Neolithic
man who gained the mutation. This is obviously sheer
madness given the variety of haplotypes etc in
northern Europe today.

In terms of dating of the origin of dairying, new
finds have changed archaeologists ideas in the last
decade or more. It seems that analysis of residue on
English pots dating to the very beginning of the
British Neolithic has indicated dairy product residue.
This is apparently supported (or at least not
contradicted) by isotopic analysis of Early Neolithic
English human bones which suggest a dairy and/or meat
diet with very little cereal component. This all
means that dairying was even present in peripheral (in
a European sense) Britain from the very beginning of
the introduction of agriculture to the island, well
before the late Neolithic period formerly proposed as
the likely date of the inception of dairying (this old
theory associated dairying with the late Neolithic
Corded Ware culture in northern Europe).

All this also makes it uncertain where dairying
arrived in Britain from and how long it had been known
on the continent. If it can be assumed that dairying
is not an indigenous innovation, then it seems to have
arrived in Britain with the beginning of the local
Neolithic. The earliest British Neolithic is usually
primarily linked to late LBK or LBK derived flow of
ideas and at least some people from somewhere between
northern France and northern Germany (Oppenheimer
links this with some haplotype I clades).

The genetic study that sparked this thread seems to
indicate that lactose tolerance was not common in the
LBK groups (far too small a sample to say it was
unknown). Analysis of age slaughter patterns of
domesticates in Neolithic Europe may point to early
dairying but it is not totally conclusive. The people
who carried out the work on the English Neolithic pot
residues indicate that they are looking to do the same
sort of analysis on continental Neolithic pots and
this should clarify the wider prehistory of dairying.


The arrival of dairying does not mean that tolerance
also 'arrived' in any meaningful way. It is uncertain
but has been suggested that the pot residues may have
been butter or cheese rather than raw milk, the
creative process of which apparently removes/ reduces
the offending lactose. I think it was about the
advantage tolerance brought to scattered unrelated
rare individuals in farms and village rather than any
major movement, although (as with everything in
archaeology) it cannot be ruled out that there was an
element of this. The ability to consume raw milk is an
undoubted selective advantage that avoids all the
energy expenditure of making cheese, butter etc. The
advantage would surely have been greatest and the
selective process most prolonged in very dairy-suited
environments where such economies dominated for
millenia-places like Ireland, upland Britain,
Scandinavia, the Alps etc. I am no expert but it
seems to me that the major differences in even crude
haplotype proportions between these dairying dominated
areas strongly argues against lactose tolerance
leading to long distance invasion and replacement by
an external group. I get the impression that the lack
of patterning suggests that lactose tolerant people
were thinly but evenly distributed across a number of
haplogroups and dairying did not confer an advantage
to any one of them.


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