Video: Gene switch causes female flies to sing like males
Female fruit flies have a hidden talent: the ability to sing like a male. All you have to do is switch on one gene 鈥� and chop off their heads.
The headless, singing females have been nicknamed 鈥渇lyPods鈥�. These decapitated flies flutter their wings to create a male mating song, a key part of courtship.
Odd as it seems, the result suggests that males and females have a lot in common. Lurking in females is the ability to act just like a male 鈥� and presumably vice versa, says , a neuroscientist at the University of Oxford, who led the study.
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鈥淵ou have a system that鈥檚 more or less unisex in most of its parts, and you have a few key nodes that you set to male or female,鈥� he says.
Mixed messages
This isn鈥檛 the first time scientists have mucked around with fruit flies鈥� sexual behaviour. Previously, researchers uncovered a male-specific gene version of the gene called fruitless that鈥檚 turned on in thousands of brain and nerve cells. Give females the male form and they court females. Take the gene away from a male, and he can鈥檛 sing for the ladies.
By artificially turning on the male fruitless gene, Miesenb枚ck鈥檚 team prompted males to sing in the absence of females. Then the researchers found that they could make the male flies croon more often by decapitating them, presumably freeing their bodies from brain signals telling them not to sing when no female is around.
鈥淲e were probably sending the fly mixed messages, and they probably didn鈥檛 know what to do,鈥� he says
Sex on the brain
When the researchers switched on the fruitless genes in female 鈥渇lyPods,鈥� they sang like males. Their melody was a little off key 鈥� but still good enough to fool other females, Miesenb枚ck says.
When the researchers rebroadcast the 鈥渇lyPod鈥� song in the presence of a mute wingless male and a willing female, the couple mated. Normally, wingless males have trouble closing the deal.
Signals from the brain probably determine whether flies sing like males or females, says , a neuroscientist at Harvard University in Cambridge, Massachusetts.
鈥淗igher up in the brain, there may other things that are happening that will be sexually dimorphic,鈥� he says.
Miesenb枚ck suspects that a few brain cells act like a master gender switch, turning on either male or female behaviours. He hopes to eventually find these cells by following the connections of the nerve cells that control the wing songs.
鈥淎t some point there must be a difference between males and females,鈥� he says.
Journal reference: (DOI: 10.1016/j.cell.2008.01.050)
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