Meeting Abstract

S5-2.3  Saturday, Jan. 5  Neuroendocrine regulation of sexual plasticity in fishes GODWIN, J*; SLANE, MA; GEMMELL, NJ; North Carolina State University; North Carolina State University; University of Otago John_Godwin@ncsu.edu

The study of sex differences has produced major insights into the organization of animal phenotypes and the regulatory mechanisms generating behavioral variation from similar genetic templates. Coral reef fishes display an extraordinary diversity of sexual expression including simultaneous hermaphroditism and functional, socially-controlled sex change. These systems provide powerful models for understanding gonadal and non-gonadal influences on behavioral and physiological variation. The Caribbean bluehead wrasse, Thalassoma bifasciatum, shows a fully male sexual behavior phenotype can develop even in the absence of gonads, key influences of the neuropeptide arginine vasotocin on sexual and aggressive behavior, and a controlling role for estrogen biosynthesis in regulating female-to-male sex change. Transduction of social cues into reproductive responses by a sex-changing female wrasse is not understood, but patterns in mammals and some neuroanatomical findings in fishes suggest the potential for direct vasotocinergic and estrogenic influences on sexual function and sex change mediated through kisspeptin effects on GnRH neurons. Advances in next generation sequencing and bioinformatics are also creating opportunities to extend genomic approaches to ‘non-model’ species. We are using these methods to examine global gene expression patterns in brain and gonads and contrast these patterns between the sexes, between alternate male reproductive phenotypes, and over the course of sex change in the bluehead wrasse. We are also extending these studies to other sex changing wrasse species to determine whether there is an evolutionarily-conserved ‘core set’ of transcriptional changes associated with sex change.