A rapid genome-wide response to Drosophila melanogaster social interactions

I used Affymetrix Drosophila Genome arrays to identify genes whose expression profiles would change rapidly due to the social interactions occurring during Drosophila melanogaster courtship. I identified 43 loci with significant expression profile changes during a 5-min exposure period. These results indicate that social interactions can lead to extremely rapid changes in mRNA abundance.The known functions of the up-regulated genes identified in this study include nervous system signaling and spermatogenesis, while the majority of down-regulated loci are implicated in immune signaling. Expression of two of the up-regulated genes, Odorant-binding protein 99b (Obp99b) and female-specific independent of transformer (fit), is controlled by the Drosophila sex-determination gene hierarchy, which regulates male and female mating behaviors and somatic differentiation. Therefore, additional identified loci may represent other long-elusive targets of Drosophila sex-determination genes.Social interactions are known to alter individual physiology, but the extent to which transcriptional or post-transcriptional mechanisms function in inducing these changes is unclear. Immediate responses are likely modulated by environmentally induced changes in synaptic signaling, which may result in alterations in gene expression with long-term consequences. Identifying the genetic basis for physiologic responses is of significant interest because it will clarify how regulated gene expression and the resulting intracellular signaling events modulate complex behaviors.Genes that control complex traits such as behaviors are difficult to identify by standard mutant analysis for two major reasons: (1) behaviors may be influenced by a large number of genes which each have a small effect, and (2) the genes involved usually have pleiotropic functions dependent upon the cellular or developmental context. Despite these limitations, Drosophila geneticists have successfully used mutant analysis to identi