Expression and SNP profiling of HSP70 gene associated with thermotolerance traits in Munjal Sheep

An investigation was carried out to identify the polymorphism of heat shock protein 70 (HSP70) gene and its expression profiling in Munjal sheep. Blood samples from 40 female Munjal sheep were collected for DNA extraction. After standardization of PCR for ovine HSP 70 gene, sequencing was carried out for single nucleotide polymorphism (SNP) profiling. Multiple sequence alignment was performed to screen SNP in the resource population and subsequently, A to G mutation was observed at c.459 position. Two genotypes viz., AG and AA were obtained. Association study revealed no significant association of identified genotypes with growth and thermotolerance traits. HSP70 expression analysis in different seasons was carried out using enzyme-linked immunosorbent assay (ELISA) kits. After blood collection, serum was separated for studying the gene expression and expression analysis of different groups was compared using t-test. Animals were also grouped in to two groups viz., heat stress susceptible (HSS) and heat stress tolerant (HST) based on heat tolerance coefficient (HTC) i.e. HST having HTC<2.40 and HSS with HTC>2.40. Statistical analysis revealed that expression of HSP70 gene varied markedly among the summer and winter season. Furthermore, a significant variation was observed between adults and lambs (P<0.05) and between HSS and HST sheep (P<0.05) for HSP70 gene expression. The expression of HSP70 was higher in adults in comparison to lambs in both summer and winter season. Selection of heat resistant animals is essential for better livestock performance amid challenging climatic conditions ahead and HSPs can be used as candidate markers for selecting resistant animals