Todd Moody Wrote:

>people are less attractive as mates.  On the other hand, if that
>new food is plentiful enough to allow for population expansion,
>the population that consumes it, though sicker than the
>population that does not, will dominate in the gene pool.


Certainly, and as we all know (believe?) this is exactly what happened
during the neolithic revolution.  I realize that you're speaking in general
terms here, but if we were to discuss how this relates to dairy I would have
to say that, IMO, there was no rennet cheese revolution, or even enough of
it around in sufficient frequency to bring about much adaptation.


>Furthermore, if you accept the neodarwinian assumption that
>adaptation is driven by random mutations, then there are no
>guarantees that adaptation will happen, no matter how long people
>are exposed to a given food.  This is especially an issue if
>adaptation requires multiple simultaneous mutations (i.e., if 3
>mutations are required to have no problems with a certain food,
>but individually those mutations confer no advantage).  This
>implies that the mere fact that people have been eating a certain
>food for a very long time does not imply that it doesn't make
>them sick; it only means that it hasn't killed them off.


I see your point that a population can survive and multiply (without being
"killed off") in the face of a food source that causes illness.  We are
living proof of that.  I also agree with your overall point (correct me if
I'm wrong) that the fact that people get sick from eating dairy products
today doesn't disprove the assertion that things like rennet-cheese may have
been a part of the human diet (however small) for as long as we've been
hunting mammals.

As for neo-darwinism, my understanding is that this line of thought does not
hold that adaptation is "driven" by random mutation.  Random mutation simply
increases genetic variability, thus rendering the gene pool more maleable in
the 'hands' of selective pressures.  In this way, I believe it is thought to
actually speed up the adaptive process, although I'm not totally sure about
that.  In any case, selection is still the driveing force.

According to Darwin and his neo-darwinian contemporaries, it is likely that,
within a given population and its survival, adaptation to a food source that
causes illness will indeed occur, (even though it might take a very long
time).  How long it takes depends largely on chance, and of course there are
no absolute guarantees.  Nevertheless, in a sense, adaptation is inevidable,
because given random variability within a population, there MUST be
individuals who are less sick (more attractive) than others.  The fact that
dairy products make so many people ill in the modern world supports the
contention that, allthough it hasn't killed us off, insufficient time has
elapsed for adaptation to fully occur.  Whether or not sufficient time is
15,000 years or 15,000,000 makes no difference to me.

On another note, has anyone ever heard the notion put forth that an
explanation for the good health of the Chineese, in the face of a carb.
dense diet, might be lack of dairy (rather than the usual conclusion of low
fat/ protein)?

Bernard "don't mind my spelling" Lischer