RENN, Suzy C.P.; HOFMANN, Hans A.; Bauer Center for Genomics Research, Harvard University; Bauer Center for Genomics Research, Harvard University: A Genomic Study of the Mechanisms of Sex-Role Behavior

Our understanding of the molecular basis of sex-role behavior is limited. While the males of most animal species compete more intensely for mates than females, there are examples of “sex role-reversed” species. The African cichlid Julidochromis marlieri has been reported to exhibit “sex-role reversal” while the closely related species J. transcriptus exhibits conventional sex-role behavior. In addition, behavioral experiments in the laboratory suggest that the females of J. marlieri exhibit increased aggressive territorial behavior as compared to J. transcriptus. In order to elucidate the genes involved in sex-role behaviors we have begun using a comparative approach to functional genomics employing the “avant guarde” technique of cross-species hybridization on cDNA microarrays. Based upon the high degree of genomics conservation due to the fact that the African Cichlid fish radiation has been extremely rapid and recent (>2000 species; <200,000 years) we are able to cross-hybridize Julidochromis RNA/cDNA to a custom-built brain-specific cDNA microarray from another African cichlid, Astototilapia (Haplochromis) burtoni. Expression profiling will identify genes that are co-regulated according to sex-role behavior rather than sex. In a complementary project, we analyze expression profiles of an experimentally sex role-reversed A. burtoni female, whose male-typical �dominance” behavior can entice other females into spawning with her. In this paradigm the gene expression changes in the brain that underlie sex-role specific behaviors can be identified independent of sex. These experiments will provide insight into the genetic basis of behavior within an evolutionary context.