Sexual dimorphism in the fly brain.
Bottom Line: Initial work found limited evidence for anatomical dimorphism in these fru+ neurons.Our analysis reveals substantial differences in wiring and gross anatomy between male and female fly brains.Reciprocal connection differences in the lateral horn offer a plausible explanation for opposing responses to sex pheromones in male and female flies.
Affiliation: Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge, UK.Show MeSH
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Mentions: The fruit fly Drosophila melanogaster displays robust, highly stereotyped and dimorphic sexual behaviors  that provide an ideal model system to study the genetic and neural basis of innate behavior. The genetic pathways that translate chromosomal sex into dimorphic behavior have been studied extensively [2, 3] (Figure 1O). Early studies using sex mosaics mapped different steps of male courtship to broad regions of the central nervous system [4, 5]. Such results suggest that there are anatomical and functional differences between the sexes in these brain regions. At the level of gross anatomy, few structural dimorphisms have been found, and most are small [6, 7]. However, three olfactory glomeruli show volume differences of 25%–60% [8, 9], and two of these have been linked to sex-specific odor processing.
Affiliation: Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge, UK.