So says David Page. I previously discussed its possible extinction here. Page mentions that the loss of a pair for the Y to combine with (or to put it another way, the mutations that resulted in “sex chromosomes”) first appeared in reptiles 300 million years ago. I was curious as to what determined sex before then, and sure enough the wikipedia page I linked to in that last post explained how at the bottom and I had simply forgotten.
Advertisement
September 6, 2011 at 12:25 pm
That was awesome.
However, I would suggest that when certain people think through the implications (eg, it is known, I believe, from fruit-fly research, that the genes that control male physiology–SRY– are separate from those that control/promote male behavior, and so Homosexuality could turn out to be a result of Y chromosome abnormality) that this research will become verboten.
September 6, 2011 at 5:52 pm
Dean Hamer was seeking a “gay gene” and people didn’t get too upset. In fact, liberals were pushing a theory of “innateness”. It’s actually politically incorrect to argue otherwise.
September 7, 2011 at 10:26 am
I think you missed my point.
Turner’s syndrome, and a number of other issues mentioned in the presentation, would seem to be due to genetic defects. However, unlike, say, Trisomy 21, which is due to an extra copy of chromosome 21, Turner’s is due to a missing X (or was thought to be due to a missing X), but their result seems to be that it is mainly due a faulty Y chromosome in the father’s germ cells that result in a completely missing Y chromosome, which, because of the lack of SRY causes them to develop anatomically as females.
That is, there is no gene for Turner’s.
My speculation was that homosexuality might turn out to be similarly a defect on the Y chromosome contributed by the father, where SRY is present, thus making the offspring anatomically male, but the genes required to masculinize the brain are defective. By any measure, that would be a genetic defect, but it would be politically incorrect to do such research. (It might only be a switch on the Y, or it might be more complex.)
September 7, 2011 at 11:33 am
“My speculation was that homosexuality might turn out to be similarly a defect on the Y chromosome contributed by the father, where SRY is present, thus making the offspring anatomically male, but the genes required to masculinize the brain are defective. By any measure, that would be a genetic defect, but it would be politically incorrect to do such research.”
If such a thing were found, the politically invested would be happy with the results because they could claim homosexuality is indeed genetic; however, what they would take issue with, vociferously and vitriolically, is that such a genetic condition is “defective.” They play word games. Have a gene or two that leaves you prone to diabetes? It’s a “genetic defect.” Have a gene or two or more that leaves you homosexual? It’s simply the “natural variety” of human nature, no matter the fact it reduces fitness.
There are two very large genetic research projects regarding gays, one at Northwestern, involving gay brothers, and one at UCLA. The UCLA study is looking at epigenetics and the fact that in one previous study years before, a higher than typical percentage of mothers of gay sons had extreme skewing of the X chromosome. The study at Northwestern in which DNA samples from about 1000 pairs of gay brothers were collected, should be written up pretty soon. They expected to have published the results long ago, but so far that hasn’t happened.
I still think Cochran has it right. Some pathogen acts upon these boys at an early age or maybe in the womb. Some genetic make-ups might be less effective in fighting off that particular germ. Or, it might be as someone on another blog said about germs: you can put a bunch of people in the same room and have a person with a flu or rhino virus cough and sneeze close to them yet many people will escape infection while others won’t. There are immune systems to consider and the mundane fact that some germs zig while others zag…chance encounters.
September 7, 2011 at 12:12 pm
“My speculation was that homosexuality might turn out to be similarly a defect on the Y chromosome contributed by the father, where SRY is present, thus making the offspring anatomically male, but the genes required to masculinize the brain are defective.”
Admittedly, I don’t know anything about genetics so I’ve a question about your speculation: you mention the germ-line defect in Turner’s and then speculate something like that might be going on in a father’s Y given to his son. If there’s a germ-line defect on a father’s Y, wouldn’t all his sons get it?
Or, at the very least, if this defect is on the father’s Y, wouldn’t homosexuality occur at a very high % in the sons of this father? While there’s some familial correlations in homosexuality, it’s not been shown to be high.
Help me understand.
September 8, 2011 at 9:11 pm
Interesting Connections, how would that be any more or less “politically correct” than alternate “gay gene” theories? Those could just as easily be described as “defective”.
Erin, I don’t think Turner’s syndrome occurs in all daughters of such men. I don’t know for a fact, but I think it would have been mentioned.