Seasonal contrast of sex difference in gene expression and splicing in somatic tissues of Rhinolophus sinicus

Most of sexually dimorphic traits can be encoded by differential gene expression between males and females. However, little is known whether this sexual difference in gene expression is consistent across different time points of the whole organism's life. Although alternative splicing, as an additional gene regulation form, is common in phenotypic diversity, its role in sexual difference relative to differential gene expression is less clear. Here, we addressed these knowledge gaps based on analyses of 45 RNA-seq somatic tissue samples collected from two different seasons. First, we reported seasonal contrast of sexual difference in gene expression and splicing. Specifically, limited differentially expressed genes between sexes (DEGs) were found in October relative to April. This seasonal pattern was also observed in differentially spliced genes (DSGs) between sexes. Gene Ontology analyses revealed divergent functional categories of these DEGs and DSG between seasons. Second, we found less overlap than expected between DEGs and DSGs in each tissue. In addition, far more number of DSGs were identified in each tissue relative to the number of DEGs. Genomic distribution patterns of DEGs and DSGs are also different (DEGs are enriched in X chromosome but not for DSGs). All these differences between DEGs and DSGs suggested contrasting roles of differential gene expression and alternative splicing in regulatory networks underlying the sexual difference.