Hi Gene,
We’ve both been around here for a while now, & I’ve very much enjoyed your contributions. I have found your religious bias almost non-existent, up until the point that that you began discussing with Schraf, I couldn’t even tell you had religion! This is a good thing!
But I respectfully disagree with you that homosexuals are (please correct me) unnatural, wrong, or any other tab you want to apply, more than any other genotype.
quote:
The stongest evidence for a genetic contribution to sexual orientation has been provided by Dean Hamer & collaborators (Hamer et al. 1993; Hu et al. 1995; Hamer & Copeland 1994). When they interviewed a large sample of gay men, they found that a much higher proportion of their male relatives on the mothers side of the family than on the fathers side were gay. This pattern suggested that a gene or genes on the X chromosome might contribute to sexual orientation, since men inherit their SINGLE X chromosome from their mothers.
To test this hypothesis, researchers used the AFFECTED PAIRS METHOD (Weiss 1993) to search for X-liked genetic markers. This method tests the hypothesis that a trait shared by pairs of relatives is caused by an allele A’ at an yet umapped locus. Suppose, that a mother ‘s X chromosome genotype were AM1/A’M2 & a father’s genotype were AM1/y, where M1 & M2 are alleles at a marker locus. Fathers transmit Y chromosomes to their sons . If A & M are linked on the X chromosome & the recombination rate is r, then 1-r of the gametes of the AA’ mother will be non-recombinant, giving rise to affected (A’ bearing) offspring who also share M2. If r=0, then M marks the trait causing locus itself, & all of the affected siblings will carry the marker allele. A strong association of a trait with a marker thus indicates that a trait is indeed affected by a gene & provides directions to it’s location.
Hamer et al. Studied 40 pairs of brothers. Using 22 polymorphic DNA markers distributed over the length of the X chromosome, Hamer et al. found that about 50% concordance for several markers in a region (Xq28) near one end of the chromosome. In a later pair of 33 brothers, they found similar results, & also showed that significantly less than 50% of heterosexual brothers of these gay men shared shared the Xq28 markers- just as predicted by the genetic hypothesis.
(Evolutionary Biology. Douglas J Futuyma. 3rd Ed. Pp. 746)
So homosexuality has been shown to have
at least one strong genetic correlation.
Cystic fibrosis is genetic (to name but a single example). Is that unnatural? Would you reserve the same feelings for these people as you would homosexuals?
Mark
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Occam's razor is not for shaving with.