Association of polymorphisms in the calpain I, calpain II and growth hormone genes with tenderness in bovine M. longissimus dorsi

The objective of this study was to determine if there is an association between tenderness in bovine M. longisimus dorsi (LD) and polymorphisms in the bovine calpain I (exons 9 & 14), calpain II (regulatory subunit) or growth hormone (intron 3) genes. Genomic DNA was isolated from bovine LD (n = 281) on which quality attributes (Warner Bratzler shear force (WBSF), sarcomere length and composition) were also characterised. DNA polymorphisms were analysed using polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis. Association analyses were performed between genotypes at the four polymorphic loci and day 14 WBSF values. It was found that the calpain 1 exon 9 genotypes had an association with WBSF such that animals with the GA genotype exhibited decreased WBSF and increased tenderness when compared to animals with the GG genotype (P < 0.05). This observation concurs with that of earlier studies, suggesting that this polymorphism is a functional marker for beef tenderness.