From: bivalve (email@example.com)
Date: Tue Jan 21 2003 - 19:22:48 EST
Comments on details of a couple of posts:
>>some simply observe that if there is no propagative benefit to this "behavior", it should have died out. Yet it continues to be manifest (in both human and non-human populations). The only explanation I have run across that makes any sense is that such a genetic link may be intertwined with some other trait which does in fact have some significant propagative benefit.<<
me: This assumes that homosexuality is an independent genetic trait (possibly linked with other genes), which is not necessarily the case. To the extent to which environmental factors play a role, homosexuality would occur in response to those rather than to genetic influences. Both social and chemical factors (within or outside the control of the person, e.g., parental treatment, choice of companions, various pollutants, steroids), as well as genetic factors, can influence sexuality. Furthermore, the genetic influence is not necessarily simply a genetic proclivity to a particular gender. For example, in mice, developing young are influenced by the hormones of adjacent individuals as well as their own. In this case, genes play an indirect role in influencing sexual development. Similarly, much homosexual behavior in animals and humans is on the part of individuals (usually males) who are promiscuous and not very discriminating, rather than genuine same-sex attraction.
An extreme example comes from the male nematodes that try to mate with their own other end. Promiscuity has the potential to be very successful, especially for males (who have a practically unlimited gamete supply), and the cost of a few mistakes may be outweighed by the success. A gene promoting such an approach could be mistaken for a gene promoting homosexuality, depending on the criteria used to determine the sexual orientation of the subjects.
The assumption that something genetic must have propagative benefit in order to persist is also incorrect. Unless a trait has a strong negative impact, it can persist, especially if it is recessive. Also, many genes are not simply on/off. A gene that automatically caused the bearer to only engage in homosexual sex, if any, would obviously not make it to the next generation. However, a gene that provides some proclivity towards homosexuality could persist as long as it did not have too great a negative impact on reproduction. For example, some genetic diseases rarely affect people before they are past their prime reproductive years. Such genes are unlikely to have sufficiently negative impacts to be weeded out of the genome. Another possibility is that a gene that is useful in one sex becomes reproductively counterproductive if expressed in the other. Such a gene could also persist.
>>I have rarely seen arguments for or against disapproval of homosexual acts put into the broader category of sexual sin<<
me: Harvest USA, at http://www.harvestusa.org/ , is a ministry that seeks to deal with all types of sexual sins, including homosexuality.
Dr. David Campbell
University of Alabama
Biodiversity & Systematics
Dept. Biological Sciences
Tuscaloosa, AL 35487-0345 USA
That is Uncle Joe, taken in the masonic regalia of a Grand Exalted Periwinkle of the Mystic Order of Whelks-P.G. Wodehouse, Romance at Droitgate Spa
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