Detection Selection Signatures for High-altitude Adaptation in Tibetan Goats

This study was aimed to screen the selection signatures on autosome of Tibetan goats and discover genes with important germplasm characteristics.Based on the Illumina 50K chip genotyping data of Tibetan goats,Xinjiang goats and Taihang goats,high quality SNP markers were obtained after filtering out SNPs with low allele frequency and not located.The genetic structure was analyzed by genetic differentiation coefficients (Fst).Meanwhile,the principal component analysis (PCA) and phylogenetic tree construction were conducted to determine the population structure.The selected genes in Tibetan goats were also identified through genome selective signals testing,which contained Di and XP-EHH with top 5% valued as a significant threshold.To identify the genes that were under selection,bioinformatics databases were examined that contained relevant data on goats.The results showed that 48 358 SNPs were identified in these three populations.Population genetic analysis showed that the three groups had similar genetic distance (Fst<0.05),but the degree of genetic differentiation of Tibetan goats (Fst=0.0376) was significantly higher than that of Xinjiang goats (Fst=0.0256) and Taihang goats (Fst=0.0257),indicating that Tibetan goats breed had already generated a certain degree of genetic differentiation.Based on these SNPs,36 SNPs and 211 genes were identified in Tibetan goats by Fst and XP-EHH.Among them,EGFR,AKT1,PDHB and PFKP genes were related to high altitude adaptation.These genes were found to be mainly enriched in purine metabolism pathway,metabolic pathway and HIF-1 signaling pathway.In conclusion,the genomic SNPs had more advantage in revealing the selection of Tibetan goats in high-altitude adaptability,and provided new theoretical references for the protection and utilization of germplasm resources.