A role for the Fem-1 gene of Drosophila melanogaster in adult courtship

The Fem family of genes influences sex determination and/or the development of sex-specific characteristics in a wide variety of organisms. Here, we describe the first mutational analysis of the Fem-1 gene of Drosophila melanogaster. The amino acid sequence of the two Drosophila Fem-1 transcripts are moderately conserved compared to that of both Fem-1 in C. elegans and the two Fem-1 transcripts in humans, with multiple ankyrin repeats. Using two transposon-induced mutations of Drosophila Fem-1, we observed striking defects in adult courtship behavior that are attributed to defects in male courting as opposed to female receptivity. Specifically, viable Fem-1 mutant males courted Fem-1 females more vigorously with an increased amount of chasing and singing than pairs of control flies. Nevertheless, Fem-1 males did not copulate at a higher frequency than controls. The above courtship defects persisted when Fem-1 males courted control females, but no phenotypes were observed when control males courted Fem-1 females. These results indicate that Drosophila Fem-1 may interact with other genes involved in courtship and sex determination. Fem-1 mutants also suppressed wing and body growth, consistent with the actions of a homologue in mice. Additional analyses of these Fem-1 alleles will help address the nature of these mutations, deepen our molecular understanding of courtship, and contribute to the evolutionary relationships among this highly conserved gene family.