Sex differences of cochlear transcriptomes in horseshoe bats

Phenotypic difference between males and females (sexual dimorphism) is widespread in animals. These sexual dimorphisms, in particular vocalizations and acoustic signals, have been shown to play important roles in mating choice and sexual selection. However, little is known about the molecular mechanisms underlying these phenotypic variations. In this study, we used four taxa of the horseshoe bats to explore patterns of gene regulations responsible for sex differences of call frequency. By analysing transcriptomes of both males and females in each taxon, we identified the genes with either differential expression or alternative splicing and some of these genes are found to be related to hearing in human or mice. Our results support that differences in the degree of phenotypic sexual dimorphism can be encoded by the magnitude of sex-biased gene expression or splicing. In addition, our results indicate that sex difference of calls may contain multiple parameters apart from the frequency component. Overall, this study provides growing evidences for supporting important roles of both gene expression changes and alternative splicing in phenotypic variations.