Analysis of expressed sequence tags of porcine skeletal muscle

Porcine skeletal muscle genes play a major role in determining muscle growth and meat quality. Therefore, to progress towards a better understanding of the genetic factors influencing these traits, the first step is to characterize the genes expressed in skeletal muscle tissue in pig. To this aim, we constructed a porcine biceps femoris muscle cDNA library and sequenced 111 randomly isolated clones. By FASTA analysis we identified 72 unique clones: 47 showed homology to previously identified genes in human or other mammals, 20 matched uncharacterized expressed sequence tags (ESTs), two showed no significant matches to sequences already present in DNA databases, and three other clones containing only repetitive elements were excluded from further analysis. Mitochondrial genes (16.2%), myosin heavy chain genes (9%) and the actin α skeletal muscle gene (9%) were the most abundant transcripts. Among the 47 identified genes several muscle-specific or predominant sequences expressed in skeletal muscle were found. The sequences of the clones matching uncharacterized human, mouse or porcine ESTs were tested by GRAIL in order to identify putative coding regions. The results of our analysis allowed the establishment of a first list of genes expressed in porcine skeletal muscle.