Phylogeny of the pheromone receptors. Phylogeny based on the amino acid sequence of the MAT A1 and MAT A2 PR (Ste3.A1 and Ste3.A2, respectively) of several red yeast species. Groups A, B and C are the same as in Figure 1. Strains marked with asterisks have both PR. MAT A1 and MAT A2 PR sequences from Microbotryum lychnidis-dioicae were used as outgroups. Bootstrap values (>50%) from 1000 replicates are shown. See Figure 1 for additional details.