Selective Sweep Analysis
The population-differentiation statistic (F ST) with Vcftools [56], nucleotide diversity (θ π) and Tajima’s D with Variscan 2.0, were estimated for 50-kb sliding windows with a 25-kb step size along each chromosome and Fisher’s exact test was performed on synonymous and non-synonymous SNPs in the exon region by Plink [57], the false discovery rate (FDR) was used to correct the P values. Windows at the top 5% of F ST and q < 0.01 of Fisher’s exact test were selected, and the corresponding genes were considered as candidates. Enrichment analysis was conducted according to Uniport and KEGG databases.