Genome-wide analysis of genetic diversity and selection signatures in three Indian sheep breeds

Abstract

Knowledge about genetic diversity and selection signatures are very essential for the management and sustainable utilization of sheep genetic resources in India. In this study, we performed a comprehensive genome-wide analysis of genetic diversity and selection signatures using SNP data. A total of 79 animals from three Indian sheep breeds: Changthangi (n = 29), Deccani (n = 24), and Garole (n = 26) genotyped with Illumina Ovine SNP50 BeadChip were included in this study. The average minor allele frequency was 0.284 with a standard deviation of 0.129. The overall mean observed (HO) and expected heterozygosity (HE) were 0.369±0.141 and 0.373±0.118, respectively. The proportion of polymorphic SNPs (PN) ranged from 0.84 (Garole) to 0.93 (Changthangi). The average pairwise genetic distance (D) ranged from 0.301 (Garole) to 0.313 (Changthangi). We identified a total of 9244 ROH segments and the genomic inbreeding coefficients ranged from 0.0673 (Deccani) to 0.1779 (Garole). Two different statistical approaches (ROH and iHS) revealed selection signatures in 37 genomic regions mapping to 188 genes across 16 of the 26 autosomes in three sheep breeds. The selective sweeps provide new insights into the local adaptation and production potential of three Indian sheep breeds. Some notable candidate genes include the TRPM8 gene involved in cold adaptation, JADE2, PLEKHB2, SPP2, TSHR, and UBE2B genes associated with meat quality traits, and the PPP3CA gene associated with fecundity.