Meeting Abstract
Adult males and females of a species often possess differences in body size (sexual size dimorphism, SSD) despite the genomic constraint of a single, shared genome. SSD results from a variety of evolutionary pressures that result in the sexes possessing differing body size optima and represents a form of intersexual conflict. One genetic mechanism that may allow the sexes to overcome the constraint of a shared genome and achieve their body size optima is differential expression of shared genes (i.e. sex-biased gene expression). To understand the role of gene expression in the evolution of SSD, we compared transcriptome expression in a lizard species with extreme male-biased SSD (brown anole) and a species that is sexually monomorphic in body size (Panamanian slender anole). We sampled two tissues that differ in phenotypic expression between the sexes in brown anoles (liver and muscle). We predicted that brown anoles would 1) exhibit high levels of sex-biased expression of the entire transcriptomes of liver and muscle and 2) express growth regulatory networks dimorphically relative to the monomorphic slender anoles. We found that brown anoles do indeed exhibit higher levels of sex-biased expression of both entire transcriptomes and growth regulatory networks in the liver and muscle compared to slender anoles. Ultimately, this work will increase our understanding of the gene expression mechanisms that could resolve intersexual conflict and facilitate the evolution of sexual dimorphisms.
