Fig. 1.

Phylogenetic analysis of 120 Rieske nonheme iron dioxygenase clusters representing 464 genes. The middle distance sequence in each cluster was used to build a tree as a representative sequence for the cluster. Numbers in parentheses identify assigned cluster numbers to be used to cross-reference with Table S2. The red branches highlight the clades and their reference genes used in this study. Clusters were grouped into five subclades (coded by color in all figures): PAH-GP, PAH dioxygenases from Gram-positive bacteria; T/B, toluene/biphenyl dioxygenases; OT-I, other dioxygenases I; PAH-GN, PAH dioxygenases from Gram-negative bacteria; OT-II, other dioxygenases II. The sizes of circles correspond to the number of members in each reference gene cluster (see Table S2 in the supplemental material for a complete list of members in each cluster).