Genetic Variability and Population Structure in Beta-lactoglobulin, Calpastain and Calpain Loci in Iranian Kurdi Sheep

Abstract

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 an Iranian breed sheep, Kurdi. Blood samples were collected from 100 pure bred Kurdi sheep from Kurdi 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 beta-lactoglobulin 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 had 2 genotypes with frequencies of 0.92 and 0.08 for AA and AB, respectively. Heterozygosity value for beta-lactoglobulin locus was 49% and for calpastatin and calpain loci was very low (24 and 8%, respectively). chi2 test confirmed the Hardy-Weinberg equilibrium for three loci in this population. These data provide evidence that Iranian's Kurdi 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 cheese characteristics, gain and meat traits and also for preservation strategies.