Identification of Heat Stress-Associated the HSPA1A (HSP70) Gene in Holstein and Turkish Grey Cattle

Genetic research focuses on breeds that adapt to harsh climatic conditions against the adverse effects of global warming in the livestock industry. Turkish Grey cattle are highly resistant to adverse climatic and natural conditions and against parasitic diseases. The HSPA1A gene encodes the HAPA1A (HSP70) protein, which protects cells against many stress factors. This study investigated polymorphisms in the HSPA1A gene by DNA sequencing in Holstein (n=70) and Turkish Grey Cattle (n=70). The 23 and 21 SNPs were detected in Turkish Grey and Holstein cattle, respectively. The six SNPs were identified in the 3´-UTR region and 18 SNPs in the exonic region (15 synonymous SNPs, 3 non-synonymous SNPs) of the gene. The three non-synonymous SNPs (nsSNP), rs382492082, rs385826597 and rs384294013 lead to Met5Ile, Met5Thr and Gly626Ala substitution, respectively. The effects of nsSNPs on protein structure and function were evaluated using ConSurf, HOPE project, SHIFT and DUET tools. The ConSurf and SHIFT analyses suggest that the amino acid substitutions are likely well-tolerated and have low evolutionary conservation, implying that these changes might not significantly impact the protein's function. In contrast, the HOPE project and DUET analyses indicate potential structural and functional disruptions caused by these mutations. Additionally, haplotype analysis indicates distinct genetic structures between Turkish Grey and Holstein cattle, suggesting diverse evolutionary pressures and historical recombination events. The SNPs identified in this study may guide genetic marker-assisted breeding to improve thermotolerance in domestic and exotic cattle.