Mutations in calpastatin and μ-calpain are associated with meat tenderness, flavor and juiciness in Hanwoo (Korean cattle): Molecular modeling of the effects of substitutions in the calpastatin/μ-calpain complex

• Haplotype (GGC) of the three CAST SNPs had a significant effect on shear force.
• G allele of CAPN1-2_T3 is associated with more tender meat in Hanwoo.
• CAPN1-2_T3 had significant effects on the tenderness score and juiciness.

The objective of this study was to evaluate the effects of seven single nucleotide polymorphisms (SNPs) in Calpain 1 and Calpastatin genes previously associated with meat tenderness attributes in other cattle breeds in Korean Hanwoo cattle. The Hanwoo resource population was used to study association of 7 SNPs with beef tenderness, flavor, juiciness, intramuscular fat and shear force. In this association study, CAST:c.182A > G (+ 0.14, P = 0.04) and CAST:c.1985G > C (− 0.12, P = 0.02) had significant effects on juiciness, but no effects on other traits. In contrast, CAPN1:c.1589G > A was associated with meat tenderness (P = 0.01) and juiciness (P = 0.04). The CAPN1:c.1589G > A (Val530Ile) SNP marker displayed significant effect on the meat tenderness score which is strongly supported by molecular modeling of the CAPN1:c.1589G > A (Val530Ile) variant that inhibits CAST protein from binding more strongly than the wild-type protein, which may explain its effect on meat tenderness.