From: SJOSEPHS@130.187.183.14 (STEVEN JOSEPHSON)
Subject: Re: Homosexuality & Evolution
Organization: Evans & Sutherland Computer Corp.
Date: Wed, 2 Sep 1992 20:09:38 GMT
X-News-Reader: VMS NEWS 1.11


In <1992Sep2.153313.28362@hilbert.cyprs.rain.com> max@hilbert.cyprs.rain.com writes:

> In article <1992Sep1.070053.7789@augean.eleceng.adelaide.edu.AU> dabbott@augean.eleceng.adelaide.edu.AU (Derek Abbott) writes:
> >
> >Does homosexuality have a useful significance within the theory of
> >evolution?
> >
> >Are there any good references that discuss this area?

I usually prefer to stay out of arguments such as this one is shaping up to be,
but in this case Max's snide tone inspires me.

> There are these buildings called libraries. They hold books in them.
> They have card catalogs. They are your friend. You may remember having
> been told to go to them before on many occasions.

Time for you to go back to yours, Max.  You are conflating two arguments, and
your explanation is misapplied.  Here's why.
 
> While you are there, you may wish to look up 'kin selection'. Under
> certain conditions a small fixed rate of homosexuality can be selected
> for. The model is that the 'uncle' or 'aunt' helps in the raising of
> the children of their siblings, and hence enhance the likelihood of their
> family genes being passed on through their kin's offspring.
> 
> This is the same explanation for why so many haplodiploidal insects
> are eusocial. In these species, males are haploid (1N chromosomes)
> while females are diploidal (2N chromosomes).
>
> For sisters, same mother and same father, their genomes will show a
> 3/4 similarity. On the other hand, a female only has 1/2 similarity
> with it's daughters. Hence, behavior that causes a eusocial insect
> to aid it's sisters is selected even more strongly than behavior which
> provides for it's offspring.
> 
> While at the library, you might also wish to look up 'naked mole rat',
> a eusocial mammal (see the recent scientific american article on them.)
> 
> 	Regards,
> 		Max

Kin selection as you have described it addresses itself more to the question of
when should an individual help a relative make babies rather than make them
themselves.  The circumstances turn out to be rather intricate, but suffice to
say that Max is correct; it is often in ones own genetic interest to help mom
make more siblings (if you are a Hymenoptera or NM rat) rather than to strike
out on your own and make babies, even if you have the equipment to do so.  This
can help to explain how some characteristics become fixed in a genetic
population once they are around even if there is some selection against them,
but it does nothing to explain how these traits came into being.

The question Max is overlooking is the big one itself - how is homosexuality
possible if it is deleterious? One of the possible answers if that this is a
"cultural" thing - something people learn rather than something they are born
with.  Unfortunately, this is not an answer, and really only begs the question
of why "culture" and our capacity to experience/generate it takes the form
that it does.  "Culture" is not an answer, it is the question *to be*
answered. 

The question here is not so much "why are some people homosexual" as "Why are 
do humans (and lots of other animals) have the capacity for homosexual 
behavior?".  The answer probably has something to do with the fact that 
homosexual behavior itself is likely not entirely deleterious, and the capacity
to pay attention to ones' environment to see what the socially (and likely
Darwinianly) successful folks are doing and imitate them certainly isn't. 
In some cultures, it is an accepted (and occasionally required) part of normal
social behavior.  This is not to say, however, that this is an entirely
"cultural" phenomena nor an entirely genetic one: to paraphrase Hartung, there
can be genetic reasons for different behaviors without there being genetic
differences between individuals.  Even asking the question of which is more
important, genes or environment (or, if you prefer, instinct vs. culture,
nature vs. nurture) is not a productive line of inquiry; it is like asking
'which is more important in determining surface area, length or width?'.  

If anyone is so inclined to take Max's original advice and hit the books, I
would suggest:

Behavioral Ecology, edited by Krebs and Davies - it is in its third edition,
but each edition is different.  The latest one came out last year. 

Peacemaking among Primates, by Frans De Waal - take a look at the chapter on
bonobos (pigmy chimpanzees) and see what he says about sexual activity and 
coalition behavior.

							Cheers,

							Josephson