On Fri, Nov 21, 2008 at 2:17 PM, Tony <[EMAIL PROTECTED]> wrote: > but if none of those homosexual men had heterosexual sisters, then eventually > it would die off. your essay, although well written seems to assume a lot and > not look at the instances like what i described above. >
You are correct, an entirely homosexual population would certainly die off (pending future technological advances). But the point I keep trying to make isn't that homosexuality is evolutionarily the bees knees (it is obviously not since it doesn't even seem to represent the majority of the individuals in the human population) but rather that it is a mistake to think that its an abomination of nature and that it is selected against evolutionarily. Lots of traits can and do wander around between a maximum frequency in the population (gets too frequent and an alternate trait is favored) and minimum frequency (the trait is favorable enough that it tends to not die out). I'll give you a real world example: Sickle cell anemia. Its a classic case studied in evolutionary biology. Sickle cell anemia is an inherited genetic disorder that distorts your red blood cells in such a way that they can't bind to oxygen molecules to transport them through your blood stream. We've known for quite some time that African American's have a much higher incidence of this disease than people of caucasian descent. And you would think that this disease would be strong selected against because it causes people to have low amounts of energy, bleed easily and usually die younger. So why would sickle cell anemia still be present in the population and in particular, why would it be so much more prevalent in people of African descent? Well, it turns out that if you have two copies of the allele that causes sickle cell anemia, you end up with sickle cell anemia. But if you only have one copy of the allele, it turns out that you have a higher resistance to malaria. Malaria has been (and still is) one of the biggest killers in sub-Saharan Africa. Consider then two people who have one allele for the gene that produces sickle cell anemia. They themselves don't have sickle cell anemia. And they are more resistent to malaria than the people around them with no copies of that allele. Lets say they have 4 kids. With basic mendellian genetics we'd say that the odds are that one child will have two copies of the allele and have sickle cell anemia, one child will have no copies of the allele but also not have a higher immunity to malaria and two children will have one copy of the allele and have higher resistence to malaria and not have sickle cell anemia. In that way, a trait that can be maladaptive in some cases (anemia) but beneficial in others (malaria) ends up maintaining a non-zero baseline frequency in the population. But if you look at people of caucasian descent, they've been living outside the tropics long enough that malaria hasn't been a problem for them for a long time and consequently the downside of anemia risks have outweighed the benefits of malaria resistance and consequently the allele has gone to a very low frequency in that population. Judah ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Adobe® ColdFusion® 8 software 8 is the most important and dramatic release to date Get the Free Trial http://ad.doubleclick.net/clk;207172674;29440083;f Archive: http://www.houseoffusion.com/groups/cf-community/message.cfm/messageid:281067 Subscription: http://www.houseoffusion.com/groups/cf-community/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=11502.10531.5
