On 12 Oct 1995, Jonathan Badger wrote:
> I'm not saying that all evolutionary approaches to behavior are wrong,
> but if it is to be accepted as science it must do more than postulate
> theories -- it must back it up with evidence. For example, if marrying
> for money is said to be genetic, the gene responsible should be able
> to be identified and sequenced, and its gene product studied to
> understand its effects. Why should sociobiology or "evolutionary
> psychology" as it likes to call itself today, be held to a lesser
> standard of evidence than the rest of biology?
The problem is that behavioral traits like this (1) are almost certainly
multigenic and (2) lead only to predisposition to a certain behavior.
These both make it incredibly difficult to study behavioral traits.
Furthermore, it is nearly impossible to do properly controlled genetic
mapping in humans because you're not able to select who procreates with
whom. Currently, the only genetic traits that can be mapped in humans
are highly penetrant, simple traits linked to single genes. Wilson knows
this, and apologizes in each of his philosophical works, saying that much
of his philosophy is still very speculative. Similarly, Gould
acknowledges that Wilson may end up being completely correct. Each
believes his model is correct, but both know that more evidence is needed.
The Human Genome Project is projected to finish in a little over ten
years. Eventually, it will be relatively simple (if non-trivial) to
sequence large portions of any individual's genome. This information and
improved informatics and computing capabilities may someday allow the
analysis and mapping of complex, multigenic traits with incomplete
penetrance. So, just because scientists are currently unable to point to
a particular gene and show that it is responsible for a particular
behavior does not mean that we will not be able to do it some day.
And while the evidence for such correlations in humans is currently
apocryphal and anecdotal, some such evidence exists in some animal
models. I am reminded, for example, of a study some years ago finding
linkage between a gene and monogomy in gophers. This isn't a
particularly ideal model system, either, but I found the correlation
intriguing. It was a single gene that linked the two. I don't know
what's become of that research, though.
J. Michael Andresen
jma at mendel.berkeley.edu
University of California at Berkeley
Department of Molecular and Cell Biology