FRASER, E.J.; RENN, S.C.P.; HOFMANN, H.A.; Harvard University, Bauer Center for Genomics Research; Harvard University, Bauer Center for Genomics Research; Harvard University, Bauer Center for Genomics Research: Sex, Sex-roles, and Dominance: A Functional Genomics Approach
How do environment and genome interact to create a phenotype? We address this question by profiling gene expression in the brain of the African cichlid fish Astatotilapia burtoni. Male A. burtoni reversibly switch between two behavioral phenotypes, dominant and subordinate, a change that is controlled by social cues. Previous work has defined neural gene expression profiles for these two phenotypes. In the absence of males, females can change their sex-role and exhibit male-typical phenotypes without changing sex. We compared neural expression profiles of dominant and subordinate females with those of males, thus controlling for the effects of sex and reproductive status, which can confound the identification of the molecular basis of social dominance. Many of the genes identified encode plausible candidates such as neurohormones, transcription factors, and structural (synaptic) proteins. Interestingly, brain expression profiles of sex-role reversed dominant females share a significant number of genes that were previously identified as �male-typical� (regardless of social status). Examples include centractin, Y-box binding protein, and elongation factor 1a. Even more striking was our finding that genes such as gonadotropin, AVT, and aromatase are up-regulated in the brains of dominant fish, regardless of sex. These results suggest that the brains of sex-role reversed females do become masculinized to some extent; however, despite the astonishing behavioral similarities, these two phenotypes are not identical at the molecular level. Microarrays are more than a mere gene discovery device. By exploiting cichlid fish plasticity and diversity we can use expression profiles to identify the molecular building blocks of complex behavioral phenotypes. Funded by NIH.
