Males, but not females, of many animal species possess ?ornaments,? conspicuous traits that function mainly in a social context. In some species, however, females also display conspicuous ornaments, resulting in reduced sexual dimorphism. Such mutually shared ornaments have long been thought to evolve in females mainly as a byproduct of selection on males, owing to the expression of the same genes in both sexes?the ?genetic correlation? hypothesis. However, little is known about the genetic basis of female ornaments. The proposed research seeks to understand the genetic basis of a female ornament, red throat coloration, in the threespine stickleback fish. The red throat coloration of male sticklebacks is well studied; thus, the recent discovery of this trait in females of some populations creates a research opportunity. In the proposed work, Quantitative Trait Loci mapping will be used to identify genomic regions associated with female and male throat coloration for crosses between populations with and without red-throated females, enabling a test of the genetic correlation hypothesis.
Sexual dimorphism is increasingly thought of as an important aspect of biodiversity. Thus this study will improve understanding of the genetic basis of a poorly explored aspect of animal diversity. Because sex differences are associated with variation in the onset, prevalence, and severity of many diseases, an improved understanding of the evolutionary genetics of sexual dimorphism may also have medical value. This project will contribute to the training of students from under-represented groups and will be featured in outreach efforts.
