Figure 4

(A): Maximum likelihood phylogenetic tree of PRX enzyme family. Unrooted tree displaying PRX animal subfamilies; AhpC-PRX1 (green), PRX5 (blue), and PRX6 (pink) that correspond with the three broad classes, typical 2-Cys PRX, atypical 2-Cys PRX, and 1-Cys PRX, respectively. Within AhpC-PRX1 orange shape denotes strongly supported monophyletic clade named PRX4. (B): Depicts zoomed in region of AhpC-PRX1 clade. Monophyletic clades comprising isoforms, PRX1/2 (turquoise) and PRX3 (purple) of Vertebrata are indicated. These isoforms were previously used to classify PRXs across all metazoan species until a revision of PRX system of classification^41,42. CNID-PRX denotes recently established subfamily found only within species belonging to phylum Cnidaria⁴³. Orange circle indicates collapsed nodes of PRX4 clade. Labels coloured blue denote sequences encoded by phylum Porifera. Black numbers on branches indicate bootstrap support. Branch lengths represent evolutionary distances, indicated by tree scale. Constructed based on edited alignment, 1000 bb and the WAG + I + G4 evolutionary model. FW: fresh water, SW: sea water.