Social and Gonadal Control of Neural Gene Expression

North Carolina State University, Raleigh NC

Investigators

Abstract

Differences between male and female brains and behavior result primarily from differences in the timing, level and location of gene expression. Even in species where sex is determined chromosomally and the gonads play central roles in the differentiation process, the exact nature of gene expression is influenced by a host of environmental influences ranging from nutrition to social interactions. Although we are building a solid understanding of how gonadal steroids influence the sexual differentiation of brain and behavior, the mechanisms by which social interactions affect this process remain poorly understood. This project develops an integrative approach to how gene expression in the brain changes during sexual differentiation, in a model system where it is possible to experimentally dissect gonadal and social influences that regulate behavior. A well-studied reef fish species, the bluehead wrasse, exhibits socially-controlled functional sex change. When local dominant males are removed, a large female changes into a male, and even gonadectomized females change to male behavioral phenotypes. The challenge is to identify those neural genes from the brain relevant to the behavior that are differentially expressed, between females that do not change sex and those that are induced to change sex in their natural environment. This project has a focus on developing the molecular technology to successfully approach that question, to first identify some of the relevant genes that then can be targeted to look for changes in expression during the behavioral change. Results will be important for further developing this system as a good genetic model to understand the neural basis of sexually dimorphic behavior. The impact of this work will extend beyond neuroscience to animal behavior, to psychology, and to potential use in aquaculture and fish breeding. In addition, the project continues excellent field and laboratory training for students in an interesting project integrating animal behavior, endocrinology and molecular biology.