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
Related in: MedlinePlus
Mentions: Places where dimorphisms change the overlap between fru+ clones are likely sites of dimorphic connectivity. We analyzed the overlap between dimorphic arbors from the 21 dimorphic clones and all other clones in our data set. This identifies many potential sites where connectivity is different in males and females (Figure 4A). For example, in male brains of the 1218 (21 dimorphic arbors × 58 clones) pairs that we examined, 665 (54.6%) have male-specific overlap (see Experimental Procedures, Figure 4B, and Movie S2). Conversely, females can form connections that are not possible in males. In females, 104 of 399 pairs (26.1%) have female-specific overlap (Figure 4A). These overlap differences include discrete changes that could reroute specific information that needs to be differentially processed in the sexes (e.g., aSP-h, aSP-f, aSP-i), as well as much larger changes that may relate to global control of sex-specific behavior (e.g., aSP-a). Our global analysis excluded ascending connections from the VNC, but visual inspection identified at least one interesting dimorphic overlap. dMS-b has male-specific dendrites in the prothoracic segment of the VNC (that appear to receive male-specific gustatory input) and shows a male-specific overlap with the dendrites of aDT-b (Figures S4B and S4C). This parallels what appears to be a direct gustatory input to these neurons .
Affiliation: Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge, UK.