Polymorphism of allelic variants of genes in dairy cow’s breed in the conditions of mountain and plain dagestan

Abstract

In the Republic of Dagestan, where livestock farming is a key area, dairy cattle breeds such as Red Steppe and Caucasian Brown have not been studied in terms of genetic identification. Variations in the PIT1, PRL and GH genes associated with milk productivity can provide important insights into the adaptation of these breeds to various environmental conditions of Dagestan - from plains to mountains and foothills. This can also reveal the unique allelic characteristics of these genes, which is the central focus of our study. The DNA used for the study was extracted from the blood of Caucasian Brown cows bred in mountain (n=74) and foothill (n=52) vertical zonality, as well as the Red Steppe breed bred in the conditions of lowland Dagestan (n=52). The studied cattle populations were genotyped by the polymerase chain reaction method – restriction fragment length polymorphism (PCR-RFLP) on a programmable fourchannel thermal cycler "Tercik" of the company "DNA-technology" (Russia). The polymerase chain reaction (PCR) was carried out using synthesized specific primers. The study of the Caucasian brown cattle breed showed differences in the genetic profiles of individuals living in different ecosystems. In mountainous areas, the allele of the pituitary transcription factor PIT-1A occurs with a frequency of 0.10, while the allele PIT-1B - with a frequency of 0.90. On the contrary, in lowland areas, the proportion of the allele PIT-1A increases to 0.18, and PIT-1B decreases to 0.82. In the mountain zone, the genotypes PIT-1AA, PIT-1BB and PIT-1AB are 2.0%, 82.0% and 16.0%, respectively. In the plain zone, the genotype PIT-1AA is not observed. Cattle raised in certain natural conditions demonstrate unique allelic combinations that are the result of adaptation to the local environment. The data obtained allow us to take these features into account and use them in further breeding work.