Investigation and validation of SNP in swine candidate genes for meat quality

Seven swine candidate genes for meat quality were investigated in order to identify informative SNPs. Molecular analyses were performed on twenty-two animals representing the extreme tails of the Gaussian distribution for three selected phenotypes (muscle compactness, fat thickness and the principal component) of 240 Large White and Landrace individuals. Among the 23 identified SNPs, 2 SNPs in the CRADD gene, 2 SNPs in the PTPRD gene and 1 SNP in the PIK3R2 gene were validated in the whole population and association analysis between genotypes and selected phenotypes was performed. These SNPs were subsequently tested in another group of 560 Italian Large White animals with extreme EBVs (Estimated Breeding Value) for fat thickness and four of them were validated in this population. Because of the important function of PIK3 in metabolic pathways involved in muscle growth, the SNP found in PIK3R2 gene was tested on 600 samples of three different Italian breeds (Large White, Duroc, Landrace) obtained from the National Association of Pig Breeders of Italy. Within each breed, the 100 individuals with the highest and the 100 individuals with the lowest values for average daily gain were analyzed and this SNP resulted polymorphic in each breed. The further step will be to verify the association between these SNPs and fat related phenotypes, thigh weight and feed conversion index.