HSP90AB1 Variations in Four Cattle Breeds Raised in Türkiye

Cattle play an essential role in ensuring global food security, yet they are encountering growing challenges from climate change. In Türkiye, cattle rearing is a fundamental aspect of agriculture, and native breeds are particularly important, even as their numbers dwindle. Understanding the genetic makeup of these breeds, especially their heat tolerance, is of great importance for sustainable livestock production. This study focused on identifying polymorphisms in the HSP90AB1 gene associated with heat tolerance in 122 cattle raised in Türkiye (Anatolian Black-AB, East Anatolian Red-EAR, Turkish Grey Steppe-TGS, and cosmopolitan Holstein Friesian-HF). The samples were respectively obtained from village herds in Antalya, Erzurum, Balıkesir, and Erzurum provinces for AB, TGS, EAR, and HF breeds. Blood samples were collected from different populations and genotyping was performed using Allele-Specific PCR. Regarding the HSP90AB1 gene, polymorphism was observed in the populations, with two alleles (C and G) and three genotypes (CC, CT, and TT), while the CC allele was not observed in TGS cattle. The frequency of the T allele was higher than that of the C allele in the studied cattle population. The TT genotype frequency ranged from 0.12 (HF) to 0.38 (TGS), while the lowest (0.00) and highest (0.35) CC frequencies were observed in TGS and HF, respectively. Significant deviation (p<0.05) from Hardy-Weinberg Equilibrium (HWE) was detected in the EAR and TGS cattle breeds with respect to the HSP90AB1 gene. As climate change intensifies environmental stresses, the adoption of molecular genetics and Marker-Assisted Selection (MAS) is necessary for the conservation of native genetic resources and the establishment of resilient livestock populations in Türkiye’s changing climate environment.