Serial Analysis of Gene Expression (SAGE) in the Skeletal Muscle of Pig

Skeletal muscle growth represents one of the main economic traits in pig production. To gain a better understanding of expressions profile in pig muscle, serial analysis of gene expression (SAGE) was performed in Longissimus dorsi of two pigs at 3 and 9 months of age. A total of 53,120 long tags were obtained and sequenced from the four muscle SAGE libraries, representing 17,902 different tags, or putative transcripts, 0.64% (±0.09) of which had a relative expression level higher than 1%o. Overall, a total of 218 tags were highly expressed and 31 had a frequency higher than 3%.Functional characterisation of the expression profiles was performed using Kyoto Encyclopedia of Genes and Genomes metabolic maps and 139 pathways were identified for swine skeletal muscle. Focal adhesion, Mitogen-Activated Protein Kinase signalling, oxidative phosphorylation, ribosomal proteins, regulation of actin cytoskeleton and insulin signalling pathways showed an abundance of genes greater than 1.5% of all the expressed transcripts. A comparison with human SAGE library indicated no statistical differences for the frequency of genes involved in these metabolic pathways.