The Gay Gene Found? - Scientists Discover “Genderblind” Gene in Flies

Researchers have discovered that by increasing or decreasing the synapse strength of cells by modifying a "genderblind" (GB) gene, fruit flies can be made to demonstrate either homosexual or heterosexual behavior, respectively.

The scientists explained that adult fly brains have dual-track sensory circuits: one track triggers heterosexual behavior, the other homosexual. In heterosexuals, the homosexual circuit is blocked by a normal suppression of synapse strength. But when the GB gene was modified to not suppress synapse strength, the homosexual circuit became unblocked.

"It was amazing. I never thought we'd be able to do that sort of thing, because sexual orientation is supposed to be hard-wired," said David Featherstone, a researcher at the University of Illinois at Chicago who lead the study. "This fundamentally changes how we think about this behavior."

Many genes don't regulate synapse strength. The GB gene is a bit different than most genes because it has the unusual ability to transmit a neurotransmitter called glutamate out of glial cells. Changing the amount of glutamate outside these cells can affect the strength of the cells' synapses. Synapses provide the means for the nervous system to connect to and control other parts of the body, and therefore they play a key role in human and animal behavior.

When the flies' synapse strength was genetically increased, the flies no longer interpreted smells the same way. Specifically, the flies did not recognize male pheromones as a repulsive stimulus. In a sense, the flies were over-stimulated.

To the researchers' surprise, they could switch the flies' sexual orientation within a few hours after GB gene modification.

The researchers explain that, while other genes that alter sexual orientation have been discovered, most just control whether the brain develops as genetically male or female. It's still unknown why a male brain chooses to do male things and a female brain does female things. The discovery of GB may help scientists understand specifically why males choose to mate with females.

The scientists also suggest that, by manipulating flies' responses to certain smells, it might be possible to domesticate them and turn them into useful pollinators instead of pests.

The study is published in Nature Neuroscience.

Via: University of Illinois at Chicago

Lisa Zyga
Science Blogger

Dec 10, 2007
by Don Carl (not verified)

This isn't going to go over well

The gay lobby will be apoplectic. Why? Because, this makes it clear that while homosexuality may be genetic, if it is it is a defect. They aren't going to like that AT ALL...

Dec 13, 2007
by Rafe (not verified)

Well if a treatment becomes

Well if a treatment becomes available they shouldn't be forced and dont' need to take it. It is a personal matter. Whatever the case there are many who are unhappy with their sexuality and would willingly take this and we have no right to stand in their path. One persons or groups standards or values cannot be forced onto another.

Dec 13, 2007
by Dave (not verified)

There are a myriad of

There are a myriad of components to sexuality, and human beings are not flies (though I've known a few that resembled wasps). There will be no "cure" for homosexuality because it is not a disease. Unfortunately, there will also be no magic shot that will eliminate ignorance and replace it with enlightenment.

Dec 14, 2007
by Rafe (not verified)

It's obvious that the

It's obvious that the manipulation of the insect pattern of behavior will fail if applied to the human system in an effort to achieve the same result. It's also clear homosexuality isn't a disorder. I think its' myopic to assume that human sexuality is so sequestered or fire-walled that scientific scrutiny will never reveal teh foundations upon how it reacts to various stimuli. When and "IF" these biological phenomena are elucidated can we really stand in the way of those that wish for some sort of intervention "IF" one is developed ?

Feb 1, 2008
by Anonymous (not verified)

gay is not something you're born with

its something you choose. whether or not i desire to kill my step father for raping me-i would indeed be a murderer if i killed him for it.

Oct 26, 2008
by Anonymous


"The gay lobby will be apoplectic. Why? Because, this makes it clear that while homosexuality may be genetic, if it is it is a defect. They aren't going to like that AT ALL..."

Well, it would be no more a 'defect' than being left-handed, or color blind. Of the three, color blindness is the least prevalent 'defect,' with homosexuality and left-handedness being roughly equal. The biggest reason why it's hard to see sexuality in the same category as left-handedness and color blindness is simply the social stigma. Remember, there was once a time when being left-handed was 'wrong' and kids were beaten if they didn't use their right hands. And it wasn't that long ago... my dad remembers being hit by his teachers for using his left hand and he's only 65.