CONVERSATIONS

Wed Jul 31 08:02:24 PDT 2024
Conversation with Tom Schoenemann

Regarding the plausibility of a continuously variable gene as in Model(c):

Tom: There was a result many years ago that most of the genes that make us
human are regulatory genes, as opposed to structural genes. Regulatory genes
influence how much of a structure is built and when. E.g. the gene that stops
the gene for making lactase when you're an adult. This gene is beneficial to
the mother, not to the child; it enables her to bear more children.

Maybe also read a chapter in a recent book by Kevin Hunt about differences
between chimps' genes and human genes. 

Fields that might find our findings interesting, because they're interested
in things like altruistic behavior: molecular evolution; reconstructing
philogeny (not really); David Sloane Wilson, debate with Richard Dawkins about
group selection. Dawkins says there is no group selection.

Sober, E., & Wilson, D. S. (1994). A critical review of philosophical work on
the units of selection problem. Philosophy of Science, 61, 534–555. Argues
that kin selection is a form of group selection. Sober & Wilson say something
like: if groups can disband and re-form quickly, then you can get group
selection. Dawkins says that if you have competition between groups, then the
groups with altruistic behavior will win against other groups but they will be
destroyed from within.

Tom recommends following up on the Sober & Wilson trail. They and/or others
have made mathematical models aimed at seeing how you could get group
selection to work.

People in evo bio talk about the frequency of an allele relative to the
rate of mutation. The rate of schizophrenia is about 1% in the
population. Likelihood of sibling having schizophrenia is about 10%.
Likelihood of identical twin being schizophrenic: about 50%. The rate of
mutation is about 1 in 10,000. If the schizophrenia gene weren't delivering a
benefit, then it shouldn't be more common than 1 in 10,000. Many debilitating
genetic diseases really do occur at about 1 in 10,000. Overt schizophrenics
almost do not reproduce at all.

Tom says it's unrealistic to have a zero rate of mutation. The main thing is
to see the conditions under which the proportion of carriers exceeds the
mutation rate.

Around 40,000 years ago, there was a dramatic increase in technology among
humans around the world. The Upper Paleolithic Explosion. A simple model:
start with relatively isolated populations and vary how often humans can
migrate from one group to another. The greater the population density, the
greater the probability that knowledge/skills will be passed on. There's a
paper that argues that there's a nonlinear relationship among inventions
spreading, which explains the technological explosion. Not a fully accepted
theory.

Tom will send a paper.

In cold periods, you get a shrinking of forests and a spread of deserts; in
warm periods, vice versa. These environmental changes push people to move.

Tom thinks it's very interesting that a changing environment can change the
degree of kin selection and thereby change the attractors in the
carrier/non-carrier dynamics.

Also, if we submit it for review, a reviewer might have yet another
suggestion.

Possible venues:
Journal of Theoretical Biology, Nature, Science, PNAS, the PLOS one (Evo Bio),
Current Anthropology (if there is clear relevance to human biology), 

Artificial Life