Genetic parameters of muscle fiber traits and association of a novel polymorphism BspCNI MYOG locus in pigs

Abstract

The porcine breeding goals are improved lean meat production and meat quality, at the same time. The muscle fiber traits is possible to account for them, because the most of it had medium or high heritability (h2 = 0.25 to 0.76) and significant genetic and phenotypic correlations with their traits. But, their traits could be only measured at carcass muscle. So, the newly molecular marker needed for selection of these traits without slaughter of breeding pig. MYOG that is one of the MyoD gene family has a crucial role during muscle fiber formation. It’s expression marks the end of the proliferation of myoblasts, lead to differentiation to myofibers by cell fusion. If the onset of MYOG gene expression is delayed because of variation in the regulatory sequences, myoblast proliferation could continue longer and increase the number of myoblast, and it lead to greater lean production. We identified a new SNP site in 5' upstream region of MYOG gene. A total of 253 pigs in Yorkshire and Landrace breeds was evaluated in this study, and they were genotyped by PCR-RFLP using BspCNI. The frequencies of TC genotype in both breeds was lower than CC genotype. C allelic frequencies were 0.86 in Yorkshire breed, 0.79 in Landrace breed. Associations between genotype and backfat thickness were highly significant (P < 0.002), loin eye area and total muscle fiber number were lowly significant (P < 0.08, 0.09), with the TC genotype animals are better than CC. But, there is not associated with meat quality. After the verification of these results from independent populations, the selection for the TC genotype animals could be improvement of the lean meat production without affecting meat quality.