Figure 1. Three divergent groups in S. cerevisiae.

PCA recognized three major groups (A, B, and C) in a combined analysis of complete sequence data for strains (N = 87) from all ecological backgrounds. The size (N) and index of association (I_A), which is a measure of linkage equilibrium, of each group are given next to the group name. The I_A of each group has been calculated using sequence data for all five loci of each strain included in that group. Strain origins are coded with symbols and colors (see legend to the left). The arrows inside group C point to fruit isolates that have been isolated from grapes but are not part of the Australian or North Carolinian sampling. Strains of particular interest due to their history as lab strains (RM11, S288c) or importance as a model fungal pathogen (YJM145) have their names attached. Numbers inside symbols indicate how many strains share this genotype. Pairwise Fst values and significance levels for comparisons by origin (left) and PCA group (right) are indicated.