Analysis of ovarian tissue transcriptome profile in Shal ewes using RNA-Seq data

The aim of this study was the investigation of gene expression profile in Shal sheep ovarian tissue using RNA sequencing data. For this purpose, the ovaries of five Shal sheep were isolated after estrous synchronization and their RNA was sequenced using Illumina Hiseq 4000 technology. On average, the data obtained from the sequencing consisted of 26638311 read pairs with 81.08 unique mapping rate. The results of bioinformatic analyzes revealed the expression of 21085 genes in Shal sheep ovarian tissue, of which 15078 genes had expression mean above 10. Gene ontology analysis revealed the significant enrichment of 162 GO terms including 41 biological processes, 46 molecular functions and 75 cellular components. KEGG pathway analysis also identified 149 significant pathways (P <0.05), most important of which were estrogen signaling pathway, TGF-beta signaling pathway and oocyte meiosis. Investigating the expression of major genes for twining and reproduction, showed a high expression for INHA, INHBA and BMPR1B, so that INHA, an important paracrine factor in ovarian follicles, was one of the 10 genes with the highest expression. Also, FSHR, ESR1 and ESR2 showed medium expression and GDF9, BMP15 and PRLR showed low expression in the samples. For the first time, in this study the ovarian tissue transcriptome of Shal ewes was comprehensively studied using RNA-Seq technology and this study can provide a useful genetic basis for a better understanding of the genes and processes involved in the Shal sheep reproduction.