GSE65628
Expression profiling of skeletal muscle in two breeds of duck (Anas platyrhynchos)
Background: Skeletal muscle growth and development is highly orchestrated in gene expressions. Understanding the location-specific and breed-specific genes and pathways are agriculturally important on meat products and meat quality. In the present study, RNA-Seq was performed to elucidate the difference of muscle deposition between locations and breeds for functional genomics studies. To achieve those goals, skeletal muscle samples were collected for pectoral muscle (PM) and leg muscle (LM) of two genetically different duck breeds, Heiwu duck (H) and Peking duck (P), at embryonic 15 days. Functional genomics studies were performed in two experiments: Experiment 1 directly compared location-specific genes between PM and LM, while Experiment 2 compared the two breeds (H and P) at the same development stage (embryonic 15 days). Results: Almost 13 million clean reads was generated using Illumina technology on each library, and more than 70% reads mapped to Anas platyrhynchos breed Peking duck genome. We identified 246, 258, 20 and 54 differentially expressed genes (DEGs) (log2.fold-change >0.5, and P-value <0.05) for H-PM vs H-LM, P-PM vs P-LM, H-LM vs P-LM and H-PM vs P-PM library, separately. A total of 168 genes were differentially expressed by over locations in experiment 1, while only 8 genes were differentially expressed by over breeds in experiment 2. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathways (KEGG) were used to functionally annotate DGEs. In experiment 1, DEGs mainly involved in Focal adhesion, PI3K-Akt signaling pathway and ECM-receptor interaction pathways (corrected P-value<0.05). In experiment 2, DEGs only associated with ribosome signal pathway (corrected P-value<0.05). In addition, quantitative real-time PCR was employed to confirm 15 differentially expressed genes detected by RNA-Seq. Conclusions: Comparative transcript analysis of leg muscle and pectoral muscle of two duck breeds not only improves our understanding of those location-specific and breed-specific genes and pathways, but also provides some candidate molecular targets for increase muscle products and meat quality by genetic control. Conclusions: Our study represents the first detailed analysis of duck breed muscle transcriptomes generated by RNA-seq technology. The optimized data analysis workflows reported here should provide a framework for comparative investigations of expression profiles. Our results show that NGS offers a comprehensive and more accurate quantitative and qualitative evaluation of mRNA content within a cell or tissue. We conclude that RNA-seq based transcriptome characterization would expedite genetic network analyses and permit the dissection of complex biologic functions. Overall design: Total RNA of duck skeletal muscle at embryonic 15 days for four group muscles was extracted using Trizol reagent (Takara, china) according to manufacturer’s instructions. Five RNA samples per group were equally mixed to get a RNA pool.