calpastatin polymorphism and its association with daily gain in kurdi sheep

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