Association of SSCP Polymorphisms of HSP70 Gene with Physiological, Production and Reproduction Performance in Sahiwal and Crossbred Cows

Abstract

Background: Cellular tolerance to heat stress is mediated by heat shock proteins (HSPs). The HSPs act as molecular chaperones and are transcribed in response to stress. Among different families of these proteins, HSP70 is considered to be related to the development of temperature tolerance. Unraveling polymorphism in heat shock protein genes could be a step towards the identification of genetic markers for selecting heat-tolerant cattle. Methods: The present study was carried out in Sahiwal (n=50) and Crossbred cows (n=50) with the objective to identify polymorphisms in HSP70 gene. Two fragments (295 and 220 bp) of HSP70 gene were subjected to Polymerase Chain Reaction-Single-Strand Conformation Polymorphism (PCR-SSCP) technique. Statistical analysis was performed to study the association of each SSCP genotype on physiological, production and reproduction traits in Sahiwal and crossbred cows using the univariate GLM model of SPSS 25. Result: The PCR-SSCP of 295 bp fragment of HSP70 gene revealed two genotypes AA and AB in Sahiwal cows and two genotypes AA and AC in crossbred cows. The association analysis revealed that genotype AA had higher peak milk yield in Sahiwal cows while the same genotype had higher total lactation milk yield, lower service period and calving interval in crossbred cows. The 220 bp fragment was found to be monomorphic in both Sahiwal and crossbred cows.