ABSTRACT
Association of genetic polymorphism in the calpastatin [CAST] gene with average daily gain was examined in Iranian purebred Kurdi sheep. The genotypes for CAST were determined by the PCR-SSCP method. Blood samples were collected from 84 purebred Kurdi sheep belonging to the Kurdi Breeding Station located in the Khorasan province, north-east of Iran. Extraction of genomic DNA was based on the Guanidinium Thiocyanate-Silica gel method. Three genotypes including aa, ab and ac with frequencies of 0.55, 0.32 and 0.13, were observed in this population. Chi-square test confirmed Hardy-Weinberg equilibrium for the CAST loci. Average heterozygosity [37%] of the CAST locus for Kurdi sheep was slightly low. Daily gain birth to weaning [GBW]; weaning to six months [GWS]; six to nine months [GSN] and nine to yearling [GNY] were analyzed by a statistical model comprising SSCP [Single strand conformation polymorphism] and significant effect [P<0.05] of CAST genotypes was observed for GBW only