POLYMORPHISM OF DAIRY PRODUCTIVITY GENES GH AND DGAT1 IN A POPULATION OF HOLSTEIN CATTLE OF DUTCH BREEDING

Abstract

This study is aimed at studying the genetic variability of the Holstein cattle breed in the DGAT1 and GH genes, which play an important role in the formation of the productive qualities of animals. The analysis was carried out with 67 Holstein cows of the Dutch breeding on an automated farm. Genotyping of polymorphisms was carried out by the allele-specific PCR method using primers. The Bos taurus reference genome (GCA_002263795,4), available in the NCBI database, was used to develop PCR primers. Primers were designed using Unipro UGENE 50,0 software. The results showed the prevalence of the A allele (0,739) over the K allele (0,261) for the DGAT1 gene with the most common genotype AA (53,7%). For the GH gene, the L allele (0,933) was dominant over the V allele (0,067). In addition, the genotype LL was found in the majority of animals (86,6%). The evaluation of the population genetic diversity included the calculation of the observed (Ho) and expected (He) heterozygosity indices, as well as the Fis fixation index. For both genes, the observed heterozygosity was slightly higher than the expected one, which was reflected in the negative Fis values (DGAT1: -0.044; GH: -0.072). Statistical analysis showed that the differences between the observed and expected heterozygosity for both genes were not significant (DGAT1: χ² = 0,131, p = 0,718; GH: χ² = 0,347, p = 0,555). This indicates that the genotype distribution corresponds to the Hardy-Weinberg equilibrium, which may indicate the absence of significant irregularities in the population, such as strong selection or inbreeding. The obtained results provide important information on the genetic structure of the Holstein cattle population in the region and can be used for further improve breeding work. Thus, the study of DGAT1 and GH gene polymorphism in Holstein cows remains a relevant topic in the field of molecular genetics of dairy cattle breeding. Further research in this area can contribute to a better understanding of the genetic mechanisms and help in the development of more effective breeding strategies.