Comprehensive identification of sexually dimorphic genes using RNA-seq with several tissues of cattle. Bos taurus

Sexual dimorphism is one of the important topic in mammal species because appearance of males and females is obvious different in all mammal species. In addition to this, molecular mechanisms also very different each other. Furthermore, it is important to employ a variety of tissues in RNA-seq experiment because recent studies imply gene expression pattern are highly tissue specific. Although previous related studies discovered numerous sexually dimorphic mechanism in mammal species, but still, many mechanisms are undiscovered in case of non-model organisms. One of the representative mammal organism is a cattle which is less researched about sexual dimorphism. For investigate bovine sexual dimorphism, we generated two-way factorial designed 40 samples RNA-seq data composed with two factors such as gender and tissues. Two statistical approaches are employed for identifying bovine sexually dimorphic genes using such two-way factorial designed RNA-seq data. As a result, we observed that detected sexually dimorphic genes exhibited strong tissue specific pattern, but fat tissue showed relatively small tissue specificity than the others. In addition, we observed that sex-related genes are shared in two mammal species such as cattle and rat through qRT-PCR experiments. Finally, we investigated pros and cons of two statistical approaches for complex structured RNA-seq analysis. Overall design: In this study, we aimed to identify genetic factors that contribute to sexual dimorphism in bovine metabolism. To achieve this goal, we have employed RNA-seq for elaborated estimation of gene expression in liver, muscle, visceral adipose tissue and pituitary gland.