Dependence of the Variability of the HSP70 Gene on Adaptation to Heat Stress in Kalmyk and Kazakh White-Headed Cattle Breeds

This study addresses an urgent problem in molecular genetics by presenting the first identification and classification of single-nucleotide polymorphisms in the 5'-untranslated region (5'-UTR) of the HSP70 gene in Kalmyk and Kazakh White-Headed cattle breeds bred in Kazakhstan.The purpose of this work was to investigate these SNPs in the 5'untranslated part of HSP70 gene in cattle of Kalmyk and Kazakh white-headed breeds using direct Sanger sequencing.A 551bp fragment of the HSP70 gene was sequenced, and the results were analyzed with BioEdit software.This analysis identified 20 single-nucleotide polymorphisms common to both breeds, with an additional five characteristic only of the Kalmyk breed and four characteristic only of the Kazakh white -headed breed.The occurrence level of these identified single-nucleotide polymorphisms varied, with frequencies for nine ranging from 3.03% to 15.15%.These results indicate a high level of polymorphism in the 5'-untranslated part of the HSP70 gene in these cattle breeds.To identify alleles of these polymorphisms, PCR-RFLP analysis was employed, specifically determining the CCGTGAGAG/ACAGCTTCCGC single-nucleotide polymorphism in the 5'-untranslated part of the HSP70 gene using MwoI endonuclease.Genotyping revealed all three genetic variants of the CCGTGAGAG/ACAGCTTCCGC SNPs in the Kazakh white-headed breed.This study on single-nucleotide polymorphisms associated with high temperature tolerance in the 5'-untranslated part of the HSP70 gene in cattle of local breeds holds both theoretical and practical significance.