Polymorphisms in µ-Calpain and Calpastatin Genes Associated with Tenderness in a Crossbred Brahman-Angus Population

Meat quality is important in customer purchasing decision and eating satisfaction. Meat quality could be described by several sensorial features, but tenderness resulting from muscle proteolysis is the most important attribute. Warner-Bratzler Shear Force (WBSF) was measured on Longissimus dorsi steaks from 581 crossbreed Angus-Brahman steers. All animals were genotyped with the 250K Bovine SNP BeadChip and data from 37 SNPs in µ-calpain and calpastatin genes were used. An association test was performed for each polymorphic SNP and for haplotypes created based on linkage disequilibrium (LD). One LD block was predicted in µ-calpain and three LD blocks in calpastatin. One SNP in calpastatin and the LD block harboring this SNP were associated with WBSF. The CG-CG diplotype (4.82±0.16 kg) was significantly different from TA-CG (4.40±0.08 kg), and both of them were significantly different from TA-TA (4.21±0.05 kg) and TG-CG (3.85±0.23 kg). A bioinformatic analysis of all 786 SNPs reported in the LD-block-3 was performed using JAVA for selection, substitutions, transcription and translation of sequences. MATCHTM was used to predict Transcription Factor Binding Sites (TFBS) and compare the effect each SNP on these TFBS. Each mRNA sequence was analyzed with RNAFold for prediction of ΔG and folding. A protein analysis was performed with Swiss-Model server and Compute-PI/MW. Twelve SNPs were found to modify TFBS and 8 SNPs were found to change the ΔG value and mRNA folding. At the protein level, 13 SNPs were able to change the value of isoelectric point, and 4 SNPs can modify protein surface.