Genetic variations in HsP90AA1 chaperone gene across diverse Indian native cattle (<i>Bos indicus</i>) breeds adapted to varied agroclimatic regions

Indian zebu cattle during their separate evolution from Bos taurus, have acquired certain changes in a set of genes that regulate the body temperature in response to heat stress. Heat shock proteins (HSPs), the abundant and ubiquitous molecular chaperones play essential role in many cellular biological processes, and are preferentially transcribed in response to heat stress. The objective of this study was to comparatively screen variants/ single nucleotide polymorphisms (SNPs) in the HSP90AA1 gene in cattle breeds, viz., Gir, Kankrej, Ladakhi, Nagori, Nimari, Ongole, Rathi and Sahiwal, adapted to different agroclimatic regions of India including the exotic breed Holstein Friesian and yak (Bos grunniens). Sanger sequencing was carried out in all the translatable exons of the gene. The analysis revealed 6 SNPs – 3 were located in exon 3, 1 SNP each in exon 4 and 6, and another SNP in exon 9. We also identified a novel SNP 2937 (G>T) nucleotide position of exon 9. Interestingly, 2 variants detected at position 1924 (A>G) of exon 3 and 2343 (T>C) of exon 6 with a frequency of 0.9 and 0.73, respectively, were found to be almost fixed in nearly all of the Indian native cattle breeds. These SNPs could potentially be utilized to undertake genotype-phenotype association studies for superior heat stress tolerance trait in Indian native cattle.