What's turning straight mice gay?
Scientists have discovered that they can turn straight female mice gay by deleting a single gene. What does this mean for human sexuality?
Researchers at the Korea Advanced Institute of Science and Technology, released some interesting findings last week. By tweaking a single gene in female mouse embryos, the scientists were able to alter the animals' sexual preference as mature mice. Here's a quick guide to the findings, and what they mean:
What exactly did the scientists discover?The geneticists who conducted the study found that by deleting one gene — the one that controls the release of an enzyme called fucose mutarotase — in female mouse embryos, they could produce adult females that behaved like males. Female mice lacking the gene avoided male mice — they wouldn't let them mount, and stopped sniffing their urine. Instead they tried to mate with other females.
Were the mutant female mice still able to get pregnant?Yes.
Why did the behavior of the mice change so dramatically?Fucose mutarotase, or FucM, apparently causes developmental changes in the brain regions that control reproductive behavior. The scientists believe that without the enzyme the female brain can't filter out estrogen, so it's exposed to extra levels of the hormone, which determines masculinity in mice. "The mutant female mouse underwent a slightly altered developmental program in the brain to resemble the male brain in terms of sexual preference," says lead researcher Chankyu Park.
Does this mean that there's a genetic link to homosexuality in humans?No, not necessarily. Researchers didn't find a "gay gene," and there's no direct corollary between mouse brains and human brains. Estrogen "masculinizes" the brains of mice, but in humans it's testosterone that has that effect. Still, the study is intriguing to scientists seeking a genetic link to homosexuality.
Where do the researchers go from here?Park says he would like to use gene-screening studies to determine if fucose mutarotase has any influence on human sexuality, but he concedes that finding test subjects may pose a challenge.