Homosexual intercourse in fruit flies

While the biological basis for homosexuality is still a mystery, a team of neuroscience biologists has reported that they may have approached the answer button.

Researcher David Featherstone, of the University of Illinois at Chicago, led the team who discovered that sexual orientation in fruit flies is controlled by an unknown nervous system regulator. With this information, the team can use gene or drug manipulation to ' turn on ' or ' turn off ' homosexual function in fruit flies for several hours.

Featherstone, a professor of biological collaboration at the University of Illinois, and colleagues discovered a particular gene in fruit flies - they called ' sex blind genes ' (GB) . GB mutations make fruit flies bisexual.

Featherstone was interested in this gene in the first place because it had the unusual ability to transport glutamate neurotransmitters out of glial cells - this is the type of cell that nourishes and supports active but neurons. dynamics are not like neurons. His previous studies have demonstrated that changes in the amount of glutamate outside the cell can alter the strength of nerve connections that play a key role in human and animal behavior.

(Artwork: ase.tufts.edu) But GB is even more surprising when postdoctoral researcher Yael Grosjean sees GB mutant male flies flirting with other males.

Feathearstone said: 'It's impressive. The GB mutant male fruit flies responded to other male flies exactly the way a normal fly reacts to a female. They even tried to mate with each other. '

A number of other genes that are capable of changing sexual orientation are also discovered, but most of them only control brain activity according to male or female sex. Why does the male brain control male activities and so for females? This is still not clear. The discovery of GB may open an opportunity to find out why males are paired with females.

Feathearstone said: 'Based on previous studies, we deduce that GB mutants have homosexual behavior because the glutame synapses have been altered in some way.' Especially these synapses are stronger than before.

He explained: ' Homosexual intercourse may be an' overreaction 'for sex agents '.

To prove this, he and his colleagues transformed the coupling strength separately from GB, and fed fruit flies to a substance that could alter nerve coupling intensity. As expected, they could ' turn ' on or off the homosexual function for several hours.

'Surprisingly. I never thought it would be possible to do such a thing because sexual orientation was supposed to be controlled. This has fundamentally changed our mind about this function. '

Featherstone and her colleagues explain the adult fly's brain has a two-way sensory circuit, which in one way stimulates opposite sex behavior, the other one controls sex-like behavior . When GB blocks glutamate synapses, the homosexual circuit is also blocked.

Subsequent studies also accurately describe this phenomenon - if GB does not block the strength of the joints, the fruit fly does not sense the smell the old way.

Featherstone said: 'Pheromone is a very strong sex stimulant. When it is released, the GB mutant flies feel pheromone differently. Especially GB mutant males no longer "prejudice" other male pheromones as an obnoxious thing. '

Featherstone said: 'One day we can tame insects such as fruit flies and take advantage of their sense of smell to turn them into pollinators rather than animals that only harm plants in vain.'

The study was published online in Nature Neuroscience .