molecular study of calpastain, calpain and beta-lactoglobulin loci in kordi sheep

the genotypes for beta-lactoglobulin (blg) and calpastatin (cast) were determined by polymerase chain reaction (pcr) and restriction enzyme digestion and genotyped for calpain (capn) by pcr-sscp method in a native iranian breed sheep, kordi. blood samples were collected from 100 pure bred kordi sheep from kordi breeding station located in shirvan, mashhad. the extraction of genomic dna was based on guanidin thiocyanate-silica gel method. after pcr reaction, amplicons were digested with restriction enzymes mspi and rsai for beta-lactoglobulin and calpastatin genes, respectively. the betalactoglobulin locus had 3 genotypes with frequencies of 0.24, 0.54 and 0.22 for aa, ab and bb, respectively; calpastatin genotypes had 2 genotypes with frequencies of 0.76 and 0.24 for mm and mn genotypes, respectively. calpain genotypes were analyzed with sscp method, which was 2 genotypes with frequencies of 0.92 and 0.08 for aa and ab, respectively. heterozygosity value for beta-lactoglobulin locus was 50% and for calpastatin and calpain loci was very low (21% and 8% respectively). χ2 test confirmed the hardy-weinberg equilibrium for three loci in this population. these data provide evidence that iranian’s kordi sheep breed have a variability, which opens interesting prospects for future selection programs, especially marker-assistant selection between different genotypes of different locus and milk and chess characteristics, gain and meat traits and also for preservation strategies.