Geneticists have found a way to alter the sexual preference of lab mice. When they bred mice that had one gene deleted, the females declined male companions and preferred instead to court other females, according to a study published yesterday in BMC Genetics. But whether these results have any implications for humans is still far from clear. Chankyu Park and his team at the Korea Advanced Institute of Science and Technology deleted the female's fucose mutarotase gene and, as a result, changed the brain's exposure to enzymes that control brain development.
The gene, fucose mutarotase (FucM), is responsible for the release of an enzyme by the same name, and seems to cause developmental changes in brain regions that control reproductive behaviors. The mice without the enzyme would refuse to let males mount them, and instead tried to copulate with other females. [AOL News]
The enzyme typically works with a protein to prevent a build-up of the hormone oestrogen in the mouse brain; extra oestrogen causes parts of female mice brains to develop like typical male mice brains. Explains Park:
"The mutant female mouse underwent a slightly altered developmental programme in the brain to resemble the male brain in terms of sexual preference." [The Telegraph]
Park has not found a "gay gene"--it's impossible to tell at this stage what relationship, if any, this study has with human sexual preferences. For one, the hormone that "masculinizes" human brains is testosterone rather than oestrogen, and the protein block isn't the same either. Still, Park hopes to investigate further to see if the study will shed any light on human sexuality.
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. [New Scientist]
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