Population structure of S. pombe.
Neighbor-joining tree (a) and the results of principal component analysis (PCA) (b) and the program STRUCTURE (c). The numbers of the strains correspond to those in Table 1. The 5 samples that strongly cluster together are colored in blue. The results of STRUCTURE with K = 4 changes when different subsets of randomly chosen SNPs are used, and the result of K = 4 shown here represents one example. The grouping of strains 15, 16, 17, 18, and 30, and the grouping of strains 2, 9, 32, and 1 are both always observed. The results of K = 2 and K = 3 are consistent.