Genome-wide transcriptome analysis of mRNAs and microRNAs in Dorset and Small Tail Han sheep to explore the regulation of fecundity.

A variety of sheep species with diverse fecundities are kept as livestock and make up the global agricultural economy. A mutation in the FecB gene has been implicated to be essential and additive for ovulation rate. To uncover potential regulators of fecundity, we performed a genome-wide analysis of mRNAs and miRNAs from Dorset sheep (Dorset), Small Tail Han sheep FecB(B)FecB(B) genotype (Han BB) and Small Tail Han sheep FecB(+)FecB(+) genotype (Han ++). Here we present detailed analyses at both the mRNA and miRNA levels to aid in the identification of candidate genes that might regulate fecundity. We found differentially expressed genes between each of the groups, which are involved in various cellular activities, such as metabolic cascades, catalytic function and signal transduction. Moreover, the miRNA profiling identified specific miRNAs unique to each group of sheep, which may play a role in the controlling fecundity differences. By exploring the miRNA-regulated gene expression network in the different sheep species we can create a stronger profile for regulation of fecundity. Furthermore, quantitative real-time PCR verified the reliability of the RNA-Seq data. To our knowledge, this is the first analysis of intravariety and intervariety in any species in this area. Taken together, this genome-wide analysis of mRNAs and miRNAs in sheep will aid in the ability to identify fecundity regulators between different sheep species.