MSN: Genetic 'switch' can turn fruit flies gay (Dec 11)

Genetic 'switch' can turn fruit flies gay
Tuesday Dec 11 12:00 AEDT

A new study has found that a combination of genetic manipulation and
drugs can transform fruit flies into homosexuals and back again in the
space of a few hours.

Scientists at the University of Illinois in Chicago discovered a gene
in fruit flies that they dubbed the "genderblind", or GB.

GB sends out a neurotransmitter called glutamate to brain cells, which
can alter the strength of the synapses that play a key role
determining human and animal behaviour.

Researchers found that a mutation of the GB gene turned flies into
bisexuals.

They also discovered that all male flies with a mutation in their GB
gene began to court other males.

"It was very dramatic," researcher David Featherstone said.

"The GB mutant males treated other males exactly the same way normal
male flies would treat a female.

"They even attempted copulation."

"Based on our previous work, we reasoned that GB mutants might show
homosexual behaviour because their … synapses were altered in some
way," Featherstone said.

Homosexual courtship could have been the result of an "over-reaction"
to sexual stimuli, he added.

To test this, researchers genetically altered the synapse strength,
independent of the GB.

They also gave flies drugs to change the synapse strength.

And, as predicted, they were able to turn homosexuality on and off
within hours.

"It was amazing," Featherstone said.

"I never thought we'd be able to do that sort of thing, because sexual
orientation is supposed to be hard-wired.

"This fundamentally changes how we think about this behaviour."