Association of the calpastatin genotypes, haplotypes, and SNPs with meat quality and fatty acid composition in two Iranian fat- and thin-tailed sheep breeds

This study was conducted to investigate the relationship between variation within Calpastatin (CAST) gene and meat quality and fatty acid profiles in fat-tailed (Chall) and thin-tailed (Zel) Iranian sheep breeds using PCR-SSCP, DNA sequence, and genotype, haplotype, and SNP effect analyses. Six previously identified SNPs including C24T, G62A, G65T, and T69- located in intron 5 and c.197A > T and c.282G > T localized in exon 6 were observed. These SNPs constituted six haplotypes of CAST-1, CAST-2, CAST-6, CAST-8, CAST-10, and CAST-11, corresponding to six genotypes of “B”, “C”, “D”, “F”, “I”, and “J”. Animals inheriting genotype “I” had lower value of shear force (P < 0.03), concentration of palmitic acid (P < 0.05), cholesterol (P < 0.05), and n−6:n−3 ratio (P < 0.02), and higher content of palmitoleic acid (P < 0.04) compared to those inheriting the other genotypes. Also, animals containing one copy of CAST-10 haplotype showed lower value of shear force (P < 0.005), lower n−6:n−3 ratio (P < 0.02), higher concentration of palmitoleic acid (P<0.04) and total mono-unsaturated fatty acid (P < 0.02) than those containing the other haplotypes. SNP effect analyses showed that three SNPs including G62A, G65T, and c.197A>T had significant effects on the content of some fatty acids and their selected ratios (P < 0.05 to P < 0.001), shear force (P = 0.006 and P < 0.001), and the cholesterol content of longissimus dorsi muscle (P < 0.05). Overall, it seems that genotype “I”, haplotype CAST-10, the “AA” genotype of SNP G62A, and the “GT” genotype of G65T SNP were the most desirable genotypes and haplotype when selecting lambs in terms of both tenderness and fatty acid composition of meat, because selecting these genotypes and this haplotype would increase tenderness and proportion of healthy fatty acids, and also decrease proportion of harmful fatty acids of meat.