If you’re a male fruit fly looking for a mate it’s important to have the right comb. Not for your hair, but on your legs. The picture on the left is a close-up of a male fruit fly’s front leg, showing specialised dark, sturdy bristles known as sex combs. These help the male to grip onto a female while mating. Researchers have discovered a short stretch of DNA that acts as a genetic ‘switch’, turning on a gene called sex combs reduced (scr) at the right time and place during fly development to create the combs. Flies lacking one copy of the switch have smaller sex combs than usual (middle) while flies missing two copies have none at all (right), similar to female flies. Figuring out how these switches control genes like scr differently in males and females is shedding light on the complex genetic circuits that govern animal development.
Written by Kat Arney
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