Home |
Search |
Today's Posts |
#9
![]() |
|||
|
|||
![]()
Gays don't chose to be gay, any more than the rest of choose to be hetero.
BS! Yes, NOYB. BS. Biological Science. Even if you want to call it a choice, there are common variations of the X chromosone among male homosexuals who make that choice. And no, all those PhD's at the end of this piece do not stand for "practicing homosexual doctor". What is rather interesting is that this information evolved from a genetic study of men who had died from AIDS. There was no predetermined objective to prove anything about genetics and homosexual behavior, that turned out to be an incidental discovery. Read and learn: CANCER FACTS National Cancer Institute National Institutes of Health A new study has found a correlation between a specific region of the X chromosome and male homosexuality. The finding represents new evidence that sexual orientation may be influenced by heredity. The study is reported in the July 16 issue of Science by scientists from the National Institutes of Health in Bethesda, Maryland. By analyzing the inheritance of genetic markers in pairs of homosexual brothers, the scientists localized the region related to sexual orientation to a minute segment of the human genome. However, a specific gene has not yet been isolated. Dean Hamer, Ph.D., chief author of the study, said, "The region that we've discovered represents a significant variation in the human genetic repertoire. If the gene itself can be isolated, then it will be important to understand how it interacts with other genes, the brain, and the environment to influence a trait as complex and variable as human sexuality." Hamer is with the National Cancer Institute and conducted the study as part of the Institute's effort to identify genetic factors involved in cancers that are frequently found in gay men infected with the AIDS virus. Hamer and colleagues studied the family histories of 114 gay men and found that their brothers, maternal uncles, and maternal male cousins were more likely to be homosexual than would be expected among the general male population. In some families, gay relatives could be traced back for three generations. Because the homosexual uncles and male cousins of the gay subjects were raised in different households, the scientists hypothesized that a genetic factor was involved. Furthermore, the maternal link suggested that homosexuality might be associated with the X chromosome, which is the sex-linked chromosome that men inherit only from their mothers. Explicit evidence for a genetic link was obtained by studying the X chromosome DNA of 40 pairs of gay brothers. The scientists used a technique called linkage mapping to search for patterns of similarity in the genetic information of related individuals. Thirty-three of the gay sibling pairs had coinherited genetic markers in the same chromosome region called Xq28, suggesting that 65 percent of the families studied were transmitting a gene for homosexual orientation. "The statistical significance of the results was better than 99 percent, which means that the possibility of obtaining our findings by chance is extremely unlikely," said Hamer. However, he noted that replication on an independent population of families will be necessary to confirm the results. The scientists do not know why 7 of the 40 pairs of gay brothers did not coinherit the Xq28 genetic marker. Hamer postulated that these gay men may have inherited other genes that are associated with homosexuality, or they might have been influenced by environmental factors or life experiences. "Given the intricacies of human behavior, it is not surprising that a single genetic locus [region] fails to account for all of the variation seen in the study group," said Hamer. "What is remarkable is that we can account for at least some of the inherited variability with a fair degree of statistical confidence." The scientists are also studying the families of lesbians. Preliminary results suggest that female sexual orientation is genetically influenced, but DNA markers have not been detected yet. Hamer emphasized that the study was not designed to test for sexual orientation. The findings do not permit determination of an individual's sexual orientation, he pointed out, because the complexities of sexuality cannot be fully explained by a gene or genes. As efforts to map the human genome progress, there will be increasing concern about how the information is used. Scientists, educators, policymakers, and the public should work together to ensure that behavioral genetics research is used to benefit all members of society and not to discriminate," said Hamer. The study is titled "A Linkage Between DNA Markers on the X Chromosome and Male Sexual Orientation." The authors are Dean H. Hamer, Ph.D., Stella Hu, M.A., Victoria L. Magnuson, Ph.D., Nan Hu, M.D., and Angela M. L. Pattatucci, Ph.D. |