Mapping of the Porcine Calpastatin Gene and Association Study of Its Variance with Economic Traits in Pigs

The objectives of this study were to confirm a location of the calpastatin (CAST) gene in chromosome 2 and to detect associations of genetic variations with economic traits in the porcine CAST gene as a candidate gene for growth and meat quality traits in pigs. Calpastatin is a specific endogenous inhibitor of calpains. The calpain protease system is ubiquitous, and is involved in numerous growth and metabolic processes. Three single nucleotide variations were identified within a 1.6 kb fragment of the porcine CAST gene and these polymorphisms were used for genetic linkage mapping. Linkage and QTL mapping were performed with the National Livestock Research Institute (NLRI) reference families using eight microsatellites and SNP makers in the CAST gene. The porcine CAST gene was mapped adjacent to the markers, SW395 and SW1695 on SSC2 with LOD scores of 15.32 and 8.50, respectively. According to the QTL mapping, a significant association was detected at 82 cM between SW395 and CAST-Hinf I for weight at the age of 30 weeks. In addition, an association study was performed with the $F_2$ animals of NLRI reference families for Hinf I, Msp I and Rsa I polymorphisms in the CAST gene. Two polymorphisms, CAST-Rsa I and CAST-Hinf I, showed significant correlation for growth traits at p<0.01 and p<0.05, respectively.