PCR-RFLP of the Ovine Calpastatin Gene and its Association with Growth

This study was designed to investigate effects of the calpastatin (CAST) genotypes determined by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) on weight traits (birth, weaning, post-weaning weights and average daily gain). A total of 359 animals (116 purebred Polypay, 110 purebred Targhee and 133 crossbred sheep) born at the Ohio Agricultural Research and Development Center (OARDC) were used. Selection of PCR primers for the bovine CAST gene was based on exons from 24 to 28 corresponded to a calcium binding domain. RFLP analysis with the Taq I restriction enzyme revealed 3 restriction sites at nucleotide positions 208, 467 and 1,198, resulting in fragments of 731, 467 (259 and 208) and 125 bp. After verification of individual sequences, differences revealed substitutions of nucleotides (A to G) at a nucleotide position 208 located in a non-coding region and newly identified sequences were submitted into GenBank with an accession number (AF285630). Genotypes were significantly associated with Birth weight (BW) and Average Daily Gain (ADG) and significant additive effects for BW and ADG and dominance effects for PW and ADG were estimated. The mixed breed revealed significantly high values for all traits comparing with purebreds, assuming that the maximized genetic effects were caused by heterosis. Analysis of breed compositions with genotypes revealed that 75% of Suffolk with AA genotypes and 50% of Targhee with BB genotypes showed significantly low PW. The calpastatin genotypes discovered by PCR-RFLP may explain variations of growth and be useful as genetic markers for a marker assisted selection program with BW and ADG.