Meeting Abstract

P3.90  Thursday, Jan. 6  Evolution of sex-biased genes in a marine copepod HARRISON, JS; Georgia Southern University sharrison@georgiasouthern.edu

Genes with sexually dimorphic expression patterns compose a significant proportion of animal genomes. These genes are the basis of sexually dimorphic phenotypes and different reproductive roles. Sex-biased genes exhibit unusual patterns of evolution compared to unbiased genes and often show accelerated rates of evolution between species. This pattern is commonly attributed to positive or sexual selection. Female-biased and male-biased genes differ in their evolutionary rates, but the pattern can vary among species. This study examines the molecular evolution of sex-biased genes among populations of the intertidal copepod Tigriopus californicus to address the following hypotheses: 1) sex-biased genes have a higher rate of non-synonymous substitutions than unbiased genes and 2) male-biased genes will be more divergent among populations than female-biased genes. Here I show that on average sex-biased genes have elevated nonsynonymous substitution rates relative to unbiased genes. There was no consistent pattern to suggest that a difference in rates of divergence exists between male-biased and female-biased genes. The results have implications for understanding the role of positive selection vs. relaxed selective constraints on the evolution of sex-biased genes.