........And part of another post, which I think raises some important
questions.

Theola

*******************

I wanted to make one more comment concerning spread of
a lactose tolerant gene among the populations of
Europe.  I am certainly not discounting the
possibility that such tolerance could have been tied
with specific haplogroups as part of the demic
diffusion process.  The evidence suggests that
sedentary farming communities reproduced more quickly
and in greater numbers than hunter-gatherer
communities.  As a result of their ever-expanding
population, it is easy to envision how a beneficial
dietary genetic mutation among these early
agriculturalists could have spread fairly quickly
among the European population.

However, one thing to consider is that if lactose
tolerance first developed in the Middle East, where
sheep and goats were first domesticated, would not the
expanding Neolithic agriculturalists into Europe
already have carried this beneficial gene?  Another
interesting point to consider is that while the
Neolithic agricultural package first arrived in
southeastern and southern Europe, why did such
tolerance remain relatively limited in comparison to
northern and northeastern Europe, where such tolerance
became much more expansive?  I assume that other
selective pressures may have eventually had an impact
on the spread of this gene, particularly ones based on
dietary subsistence.  For example, if certain
populations in northern Europe became more
significantly reliant on domesticated sheep and cattle
for subsistence, then additional selective pressure
would have favored the spread of this gene than would
have been present among southern European and Middle
Eastern groups, which may have relied more on plant
resources.