Assessment of calpastatin and insulin-like growth factor 1 genotypes in Tsigai sheep

The aim of the present study was to evaluate the genotypic distribution of calpastatin (CAST) and insulin-like growth factor 1 (IGF1) gene polymorphisms in the Tsigai sheep breed. Genomic DNA was isolated from blood samples by the phenol-chloroform method. A total of 56 sheep were genotyped by the PCR-RFLP method. Allele and genotype frequencies were calculated by the standard procedures. To evaluate the population-genetic properties, the Hardy–Weinberg Equilibrium (HWE) testing was performed. Moreover, genetic diversity was evaluated through gene heterozygosity (He), effective allele numbers (Ne), polymorphism information content (PIC), the level of possible variability realization (V%), the fixation index (FIS), and the Shannon-Weaver diversity index (H´) were estimated. Results revealed that the frequency of the heterozygous genotype (0.64) was remarkably higher than the homozygotes in the CAST locus. HWE testing showed a deviation (P<0.05) and the estimation of population genetic parameters indicated a moderate genetic variability in the CAST marker. Concerning IGF1, the Tsigai population was found to be monomorphic. In this context, all the animals were genotyped as the BB. The results provided by the present study may be useful in evaluating the genetic structure of the Tsigai sheep breed for which limited information is available.