ПОРОДНІ ОСОБЛИВОСТІ АЛЕЛЬНОГО ПРОФІЛЮ ГЕНІВ PIT1 ТА GH УКРАЇНСЬКОЇ АБОРИГЕННОЇ ЛЕБЕДИНСЬКОЇ ПОРОДИ КОРІВ

Abstract

The preservation of genetic diversity is a paramount concern in addressing global challenges today. The foundation of biological diversity hinges on its genetic components, and the loss of species and genetic variability poses a genuine threat to the biosphere. This is because the sustainability of natural ecosystems and agroecosystems depends directly on their genetic adaptability to changing environmental conditions.
 In cattle, genes associated with milk yield play a crucial role, including genes related to milk proteins and hormones. Among these, the pituitary-specific transcription factor (PIT1) and growth hormone (GH) genes are of particular significance. In this study, we investigated the polymorphism of these genes in the Lebedyn breed of cattle.
 A total of 2 gene polymorphisms, PIT1 and GH, were examined through molecular and genetic research conducted at the genetics laboratory of the Institute of Animal Breeding and Genetics named after M. V. Zubets, part of the National Academy of Agrarian Science of Ukraine. The study utilized 32 DNA samples extracted from the venous blood of Lebedyn breed cows using the 'DNA Sorb-B' kit from AmpliSens. Genotyping was carried out through polymerase chain reaction (PCR-RFLP) analysis of restriction fragment length polymorphism, employing the “Tertsyk” amplifier for PCR. The resulting DNA restriction analysis products were assessed via electrophoresis in a 2–3% agarose gel containing ethidium bromide, with DNA fragment lengths determined using the GeneRuler TM 50 bp DNA Ladder and Thermo Scientific™ GeneRuler 1 kb Plus DNA Ladder markers.
 For the PIT1 gene analysis, a 451 bp amplified fragment was treated with the enzyme HinfI, yielding the following allele frequencies: A (0.38) and B (0.62). The heterozygous AB genotype was the most prevalent (0.45), while homozygotes for the A allele constituted 0.15 of the population. In the case of the GH gene fragment (223 bp), hydrolysis was performed using the restriction enzyme AluI. Analysis of allele frequency distribution indicated a high frequency of the L allele (0.85), with no animals exhibiting the homozygous GHVV genotype, and the GHLL genotype was present in 0.7 of the population.
 These findings reveal unique features of the allelic spectrum of the PIT1 (V-0.62) and GH (L-0.85) genes specific to the Ukrainian indigenous Lebedyn breed of cows. Selectionally significant genotypes include PIT1AA (15%) and GHLL (70%), while heterozygote carriers, which contribute to genetic diversity within the population, account for 45% and 30%, respectively.
 This study’s results hold particular value due to the alarming decline in the population of local indigenous breeds and the imminent threat to the preservation of agricultural genetic resources.