The genetic architecture of odor-guided behavior in Drosophila melanogaster

The avoidance response to repellent odorants in Drosophila melanogaster, a response essential for survival, provides an advantageous model for studies on the genetic architecture of behavior. Transposon tagging in a highly in bred strain of flies in combination with a rapid and simple statistical beh avioral assay enables the identification of not only large phenotypic effec ts, but also small aberrations from wild-type avoidance behavior. The recen t completion of the sequence of the Drosophila genome facilitates the molec ular characterization of transposon-tagged genes and correlation between ge ne expression and behavior in smell-Impaired (smi) mutant lines. Quantitati ve genetic analyses of a collection of smi lines in a coisogenic background revealed an extensive network of epistatic interactions among genes that s hape the olfactory avoidance response. The identification and functional ch aracterization of proteins encoded by smi genes that form part of the olfac tory subgenome and correlation of polymorphisms in these genes with variati on in odor-guided behavior in natural populations will advance our understa nding of the genetic architecture of chemosensory behavior.