Fig. 3.

—Non-japonica variants present in the aromatic group. (a) Joint allele frequency spectrum summarizing frequency distribution of major aromatic alleles and their occurrence in japonica. Logarithmic transformation was used for the observed frequencies. The largest fraction of the examined sites is invariant in the two groups (the top-right field); however, 100,016 major aromatic alleles are rare or absent in japonica (the bottom row). (b) PCA constructed from the 100,016 sites identified above.