Gene switches sexual desires in mice.

Jenny - posted on 07/12/2010 ( 12 moms have responded )

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http://www.newscientist.com/article/mg20...
Gene switches sexual desires of female mice
09 July 2010 by Andy Coghlan

A GENE has been discovered that appears to dictate the sexual preferences of female mice. Delete the gene and the modified mice reject the advances of the males and attempt to mate with other females instead.

While it is impossible to say whether the finding has any relevance for human sexuality, it provides a clue as to how sexuality develops in mammals.

Chankyu Park and colleagues at the Korea Advanced Institute of Science and Technology in Daejon, South Korea, deleted the FucM gene in mouse embryos to see what effect it would have on behaviour.

Female mice lacking the gene avoided the advances of males, stopped sniffing male urine and attempted to mate with other females, though their ability to have pups was unaffected (BMC Genetics, DOI: 10.1186/1471-2156-11-62).

The gene the team deleted is for an enzyme called fucose mutarotase, which adds the sugar fucose to proteins. Park believes that disabling the gene exposes parts of the developing mouse brain linked with sexual preference in adult life to extra oestrogen. The hormone masculinises the brain in mice - though not in people.

In a normal female mouse fetus, this extra oestrogen would be "filtered out" by a substance called alpha-fetoprotein. But AFP only functions properly when adorned with fucose. So without the gene that makes the enzyme, AFP cannot keep the flood of oestrogen at bay.

As a result, the female mouse brain develops as if it were a male. "The mutant female mouse underwent a slightly altered developmental program in the brain to resemble the male brain in terms of sexual preference," says Park.

Supporting the claim, Park's team also report finding lower than usual concentrations of fucose-laden AFP in a female mouse embryo missing the crucial gene.

The results also make sense in light of the experiments in 2006 by Julie Bakker of the University of Liège in Belgium, who found that female mice became masculinised when the gene for AFP was deleted.

Now, Park and his colleagues are hoping to use gene screening studies to find out whether fucose mutarotase has any association with sexual orientation in humans. He admits this research may be "very difficult", partly because it will not be easy to find a suitable number of volunteers.

Simon LeVay, who researches the origins of sexuality, says that the Korean study is not directly relevant to the issue of human sexual orientation. As he points out, it is testosterone not oestrogen that masculinises the human brain, and human AFP doesn't prevent oestrogen from entering the brain as it does in mice.

"Nevertheless, it is probably only a matter of time before molecular geneticists identify genes that influence sexual orientation in humans," says LeVay.

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Andrea - posted on 07/13/2010

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sighs and shakes head They would try to find a cure for being gay, very disappointed.

Rosie - posted on 07/13/2010

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very interesting, but you do know that if this gets proven to be true in humans, you'll have all the people out therre questioning bisexuals even more.

Jessica - posted on 07/12/2010

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That is very interesting! Though I also don't think its a "choice," I doubt they will find one gene that controls sexual preference with humans... I just think there's probably a lot more factors that go into it, kwim? We're a bit more complex than mice when it comes to sexuality.

Katherine - posted on 07/12/2010

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Back in 'the day' I used to think it was a choice. Now in my "infinite" wisdom I believe it's genetic. So now all of those jerks can can it.

Jenny - posted on 07/12/2010

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Yes Christa but it's start in the right direction. We're making big headway in genetics, it's only a matter of time.

Christa - posted on 07/12/2010

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Good thing mice aren't humans, it doesn't prove anything and that's all I'll say on this topic because we all know what happens . . .

Jenny - posted on 07/12/2010

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I just hope once the gene for humans is found people don't see it as way to "fix" LBGT indivduals as IMO, they are not broken.

Iris - posted on 07/12/2010

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Finally something! Even though it's only mice I think it's just a matter of time. But no matter if they can come up with scientific proof or not, I'll always believe that homosexuality is NOT a choice.

[deleted account]

It's not a surprise to me as I have always believed that sexual orientation is NOT a choice. I know we are only talking about mice now but I think that this theory applies to humans as well.

Krista - posted on 07/12/2010

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VERY interesting! Thanks, Jenny! I've never understood these people who say that people "choose" to be gay. I don't recall ever choosing to be straight (although I would make an exception for Rachel Maddow, thankyouverymuch.)

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