The evolutionary causes and consequences of sex-biased gene expression

Females and males often differ extensively in their physical traits. This sexual dimorphism is largely caused by differences in gene expression. Recent advances in genomics, such as RNA sequencing (RNA-seq), have revealed the nature and extent of sex-biased gene expression in diverse species. Here we highlight new findings regarding the causes of sex-biased expression, including sexual antagonism and incomplete dosage compensation. We also discuss how sex-biased expression can accelerate the evolution of sex-linked genes.