Analysis of selection signatures reveals important insights into the adaptability of high-altitude Indian sheep breed Changthangi

Changthangi is a high-altitude sheep breed of India that is adapted to cold and hypoxic climate of Himalayas. In the present study, we analysed population structure of Changthangi and contrasted it with selected Indian and European commercial sheep breeds to detect genomic regions under positive selection. The studied domesticated sheep breeds included Changthangi, Indian Garole, Deccani, Tibetan, Rambouillet and Australian Merino. While the PCA results revealed Changthangi clustered with Tibetan sheep; TREEMIX and ADMIXTURE results also detected the introgression of lowland Indian sheep inheritance in Changthangi. Cross-population comparisons of Changthangi using XP-EHH showed multiple functional regions present on OAR 7, 15 and 16, to be under selection in Changthangi sheep. These regions are related to adaptation to climatic and hypoxic stressors, nervous system and mitochondrial functioning. The genes present in these regions are suitable candidates for future studies on the genetic mechanisms underlying high-altitude adaptation.