Sex on the brain: ‘Doublesex’ gene key to determining fruit fly gender

The fruit fly

New research published in Nature Neuroscience today shows that the ‘doublesex‘ (dsx) gene responsible for gender and body shape in the fruit fly is also responsible for determining the architecture of their brains and nervous system for sexual behaviour.

Previously, the gene known as ‘fruitless‘ (fru) was thought to be responsible for the male-specific behaviours. However, Dr Stephen Goodwin’s group at the University of Oxford have shown that it is a combination of both dsx and fru acting together that leads to the neuronal ‘wiring’ that determines male-specific sexual behaviour. Similarly, disruption of the synaptic activity of dsx-expressing neurons in the female brain led to a lack of response or co-operation during courtship and copulation.

Unlike fru, which is only conserved in the genome of insects, dsx is found throughout the animal kingdom where it is already known to play a fundamental role in sex determination. So, could dsx be responsible for more than the fruitiness of just flies? Further work on dsx is needed before we can make any bold claims about that, but the work of Rideout et al. points the way.

• Rideout E, et al. Control of sexual differentiation and behavior by the doublesex gene in Drosophila melanogaster.
  Nature Neuroscience, 2010 (Epub ahead of print, doi: 10.1038/nn.2515)

Image credit: Anne Weston and Wellcome Images