The goal of this research proposal is the molecular isolation and characterization of a novel gene named Casanova (cas),which is involved with the regulation of sex-specific behavior in Drosophila. Further characterization of the cas phenotype will determine the type behavioral abnormalities involved. P-element mutagenesis will be used to create deletions removing the cas gene or new alleles. New deletions will be used to further map the position of the cas gene to the smallest possible region. Characterized phage and cosmid clones, located within the region will be ordered and placed relative to their position on the deletion lines. Restriction fragments which identify transcription units and are placed within the smallest cas containing region will be used for the isolation of cDNA clones.