Comparison of transcriptome profiles between bulls and steers in the longissimus dorsi muscle of Korean cattle

Purpose: The goals of this study are to determine effects of castration on gene expression in longissimus dorsi muscle by comparing transcriptome profiles and to search candidate genes related with beef quality like flavor, tenderness, juiciness and fat deposition Methods: longissimus dorsi muscle mRNA profiles of 3 bulls and 3 steers of Korean cattles were generated by RNA sequencing using Illumina NextSeq 500. After quality checking, Tophat2 software was used for read mapping, and EdgeR was used to identify differentially expressed genes (DEGs) between bulls and steers. Gene ontology pathway analysis on DEGs was conducted with DAVID tool for categorization of DEGs. Results: Using an optimized data analysis workflow, we mapped about 58 million sequence reads per sample to the bovine genome (build UMD3.1) and identified 18,027 expressed genes in the longissimus dorsi muscle of bulls and steers with TopHat2 workflow. RNA-seq data confirmed 1,146 differentially expressed genes (adjusted p-value, FDR <0.05). Conclusions: We comparatively analyzed the transcriptome profile from longissimus dorsi muscle of bulls and steers of Korean cattles using NGS and identified DEGs between bulls and steers. The functional annotation analysis of DEGs found that transcriptome profile difference in longissimus dorsi muscle by castration. Overall design: longissimus dorsi muscle mRNA profiles of bulls and steers were generated by RNA sequencing using Illumina NextSeq 500.