This link has been bookmarked by 8 people . It was first bookmarked on 30 Mar 2008, by someone privately.
-
24 Apr 15
-
Bocklandt is quick to point out that most likely there is no single “gay gene”—no single switch for sexual orientation. Instead, there are probably a handful of genes that work in ways as yet unexplained
-
Some conservatives argue that homosexuality is a personal choice or the result of environmental influences. Some gay rights activists insist that homosexuality is genetic, hoping that proof from that domain will lead to greater acceptance. Still others, backing the same cause, discourage any investigation into the biological origins of sexual orientation, fearful that positive results will lead to attempts to rid the world of potential homosexuals. A handful of scientists, though, are just curious. For them, the discovery of how an individual becomes gay is likely to shed light on how sexuality-related genes build brains, how people of any persuasion are attracted to each other, and perhaps even how homosexuality evolved.
-
He thinks it is likely that perhaps 5 to 15 genes explain sexual orientation in most people.
-
Sven Bocklandt
-
Hamer had just published a study that claimed not only to have finally proved that male homosexuality was at least partially genetic but also to have pinpointed the stretch of chromosome where one of the genes involved resided. Hamer and his colleagues conducted extensive interviews with 76 pairs of gay brothers and their family members and found that homosexuality seemed to be inherited through the maternal line. This led him to compare the X chromosomes—which can be inherited only from the mother—in those same brothers. There he discovered a shared genetic marker, a patch of DNA called Xq28. Interviews with the subjects also revealed them to be either gay or straight.
-
Sven Bocklandt of UCLA's medical school studies
the DNA of gay and straight male twins. -
Whether or not a gay gene, a set of gay genes, or some other biological mechanism is ever found, one thing is clear: The environment a child grows up in has nothing to do with what makes most gay men gay. Two of the most convincing studies have proved conclusively that sexual orientation in men has a genetic cause.
-
William Reiner, a psychiatrist at the University of Oklahoma Health Sciences Center, explored the question of environmental influences on sexuality with a group that had been surgically shifted from boys to girls.
-
the boys were surgically made into girls at birth.
-
Invariably, Reiner found that the faux females ended up being attracted to women.
-
If societal nudging was what made men gay, at least one of these boys should have grown up to be attracted to men. There is no documented case of that happening.
-
The solution to that question is exactly what Bocklandt is trying to find. By looking not at DNA but at where DNA is switched off, he hopes to find the true genetic seat of homosexuality. Hamer looked at broad regions of chromosomes using genetic markers, a low-resolution result that tells little more than “something’s going on somewhere around here.” Bocklandt is hoping to look with a much stronger magnifying glass at the areas Hamer’s research highlighted. If he succeeds, it will be a triumph not only for the genetics of homosexuality but also for genetic research in general.
-
-
01 Mar 12
-
Some conservatives argue that homosexuality is a personal choice or the result of environmental influences. Some gay rights activists insist that homosexuality is genetic, hoping that proof from that domain will lead to greater acceptance.
-
the discovery of how an individual becomes gay is likely to shed light on how sexuality-related genes build brains, how people of any persuasion are attracted to each other, and perhaps even how homosexuality evolved.
-
76 pairs of gay brothers and their family members and found that homosexuality seemed to be inherited through the maternal line.
-
There he discovered a shared genetic marker, a patch of DNA called Xq28.
-
The environment a child grows up in has nothing to do with what makes most gay men gay. Two of the most convincing studies have proved conclusively that sexual orientation in men has a genetic cause.
-
William Reiner, a psychiatrist at the University of Oklahoma Health Sciences Center, explored the question of environmental influences on sexuality with a group that had been surgically shifted from boys to girls. These boys had been born with certain genital deformities; because it is easier to fashion a vagina than a penis, the boys were surgically made into girls at birth. In many cases they were raised as girls, kept in the dark about the surgery, and thought themselves female long into adulthood. Invariably, Reiner found that the faux females ended up being attracted to women. If societal nudging was what made men gay, at least one of these boys should have grown up to be attracted to men. There is no documented case of that happening.
-
The second study was an examination of twins by psychologist Michael Bailey of Northwestern University. Among identical twins, he found that if one was gay, the other had a 50 percent chance of also being gay. Among fraternal twins, who do not share the same DNA, there was only a 20 percent chance.
-
At first glance, those results seem to suggest that at least some homosexuality must not be genetic. Identical twins have the same genes, right? How could one turn out gay and the other not gay as often as 50 percent of the time? There are many other traits that are not always the same in identical twins, however, like eye color and fingerprints. The interesting question is, how do any of these major differences arise between two products of the same code?
-
Bocklandt has collected DNA from two groups of 15 pairs of identical twins. In one group, both twins are gay. In the second, one twin is gay, and the other is straight. Identical twins have the same DNA, but the activity of their genes isn’t necessarily the same. The reason is something called methylation.
-
So even though we inherit two copies of every gene—one from our mother, one from our father—whether the gene is methylated often determines which of the two genes will be turned on. Methylation is inherited, just as DNA is. But unlike DNA, which has an enzyme that proofreads both the original and the copy to minimize errors, methylation has no built-in checks. It can change from one generation to the next and may be influenced by diet or environment. It’s in this mutability that Bocklandt hopes to find the secret, by seeing which flipped genetic switches correlate with homosexuality.
“For each pair we expect to see a whole lot of things that are random—sometimes someone smoked, or medication was used for long periods of time,” Bocklandt says. “But basically we compare the gay results with the straight ones and see if any region shows up multiple times for these subjects.”
-
Methylation turns off certain sections of genetic code.
-
-
15 Sep 10
-
24 Feb 08
Would you like to comment?
Join Diigo for a free account, or sign in if you are already a member.