Tom Bri:
> I am not saying that paleo people got much milk. And I am not saying
> that
> neolithic people made the transition to milk drinking quickly. Just
> trying
> to point out that even most lactose intolerant people can and do drink
> milk
> without much obvious effect.

Yes, I also know people of African and Asian ancestry who can drink milk
without obvious symptoms. I don't know whether that's true for most or not,
but I wouldn't be surprised if most people without any of the lactose
tolerance genes who have been drinking milk regularly for some time can do
so without obviously-connected symptoms. I think if they stopped drinking it
for a month or two and then started up again they might be more likely to
have such symptoms, however. Even among European Americans, infants and
children commonly have problems digesting milk at first. Doctors often
advise, "Don't worry, they'll get used to it" or "They'll grow out of it and
then they'll be able to drink plenty of healthy milk." Rather than
permanently "growing out of" their intolerance to milk, I suspect that many
(though probably not all) European Americans who were sensitive in their
childhood might again develop symptoms (at least temporarily) if they
stopped eating all dairy for a time--probably more so if they went totally
Paleo.

> My guess is that early domesticated cows were kept for ease of having
> meat
> on hand, and maybe blood drinking like some Africans still do. Milk
> drinking
> was probably a much later innovation.

That's my sense as well.

> As to how significant the effects would have to be to give lactose
> tolerant
> people the boost. A selective advantage does not have to be all that
> great
> to have a big effect over several thousand years time.

Still, almost 10 times as many descendants? "[O]ne of the strongest genetic
signatures of natural selection yet reported in humans"? That seems like a
pretty big advantage. The article calls it "an enormous selective
advantage." And the hypothesis of dehydration from diarrhea is a fairly
significant symptom, though it is speculation at this point and the early
societies with some milk drinkers may have started drinking milk in greater
numbers after they discovered techniques like fermentation that reduced
their symptoms to tolerable levels.