摘要：The article presents the results of genotyping of 156 Simmental cows for the genes of kappa casein ( CSN3 ), beta-lactoglobulin ( BLG ), alpha-lactalbumin ( LALBA ) and leptin ( LEP ). Studies have shown that the population for all genes is in a state of equilibrium distribution of genotypes, which indicates the absence of factors that change allele frequencies. For the CSN3 gene, the frequency of genotypes A/A , A/B , and B/B is 0.583, 0.385, and 0.032; alleles A and B - 0.776 and 0.224. For the BLG gene, the frequency of the corresponding genotypes is 0.449, 0.455, and 0.096; alleles A and B - 0.676 and 0.324. The occurrence of the LALBA gene genotypes is as follows: A / A – 0.513, A/B – 0.429, B/B – 0.058; allele A – 0.728, allele B – 0.272. Distribution of genotypic classes of the LEP gene: C/C – 0.429, C/T – 0.481, T/T – 0.09; frequency of alleles C and T – 0.67 and 0.33. The observed population structure with a low frequency of B/B genotypes for the CSN3 and BLG genes associated with protein-milkability, but a relatively high level of heterozygosity, demonstrates a stable equilibrium of allele frequencies, which is possible in the case of selection in favor of heterozygotes.
