2.3. Genetic Diversity and Haplotype Network

Indices of genetic diversity (F_ST, θs, and θπ) and the site-frequency spectrum (Tajima’s D and Fu’s Fs) were estimated by Arlequin v3.5.1.3 [19]. Tajima’s D and Fu’s Fs estimated the deviance between segregating sites and nucleotide diversity to infer the demographic change against the null constant size model. The increasing rare alleles after population expansion will inflate θs relative to θπ and resulted in negative Tajima’s D and Fu’s Fs. To show the relationships between cpDNA haplotypes (chlorotypes), a pairwise-distance haplotype network was built with the minimum spanning tree (MST) algorithm in Arlequin v3.5.1.3 [19].