Isolation of differentially expressed genes related with ham saltino loss in Italian heavy pig

We used Fluoro Differential Display (FDD) technique to search candidate genes for salting loss (SL) ham in Italian heavy pig. A group of 277 Large White pigs, 183 females and 94 castrated males were slaughtered. Four unrelated animals (2 females and 2 castrated males) with the lowest SL index, and 4 with the highest SL index were selected. Total RNA was extracted from a sample of semitendinosus muscle of each animal and collected in two pools, one for each group of pigs. The FDD protocol, utilized to identify differentially expressed genes between the two groups, gave fingerprints composed of about 50 well distinct bands in the size range of 200-1500 bp. On the whole about 5000 different cDNAs fragments were separated and analysed. Among these bands, we found 12 strongly differentially–expressed bands, always over expressed on the pool with the highest weight loss. The DNA extracted from the bands was sequenced and similarity was found to 6 known genes, to 4 gene with an uncharacterized function, and to one L1 interspersed element. Four of these genes, Sarcolipin (SLN), Triadin (TRDN), Titin (TTN) and Down syndrome critical region 1 (DSCR1) are mostly expressed in the skeletal and cardiac muscle and could be involved in the determination of meat quality in pigs. Before to consider these genes for association studies, these results needs to be validated by an alternative method of evaluation of gene expression.