On Monday, September 5, 2005, at 08:08  PM, Jerry Stegenga wrote:

>
> 10,000 years is recent and that applies to all  humans.
>

Depends on what genetic mechanism is involved. Some adaptation can be
very fast. For example I read a while back that a black skinned people
will turn white or vice versa in about 6000 years if they change
environments. Milk drinking is merely an extension of an already
existent trait, not something completely new. I don't claim to know,
but I suspect adaptation might be pretty fast, especially if, as with
diabetes, the result is strongly debilitating. For example, diabetes
rises and falls in a few generations after adopting a western style
diet for groups that are not previously adapted to it. That might be
caused by bread, or milk, or something else. But diabetes rates do fall
after a few generations.