Sex-biased protein expression in threespine stickleback, Gasterosteus aculeatus.

In the threespine stickleback, males and females are sexually dimorphic, having slight differences in body morphology but pronounced differences in reproductive behaviors and phenotype during the mating season. Recent interest in sex chromosome evolution and sex-specific gene expression has surged toward understanding the molecular basis of sexual dimorphism in this species. Sex-biased gene expression at the transcriptome level in liver tissue of nonreproductively active fish was reported recently, yet proteome level investigations in the species are scarce.