Fig. 3

Maximum likelihood phylogenetic tree of SOD enzyme family. Unrooted tree displaying CuZn and Mn SOD sequences that are convergently arisen evolutionary groups. Filled in coloured shapes indicate monophyletic group; SOD1 (pink), SOD2 (turquoise), Rsod (green) and SOD2X (purple). The yellow box indicates the monophyletic group comprising CuZnSOD sequences from ancestral cyanobacteria, Pseudanabaena sp. and Gloeobacter violaceus [38]. SOD3 is paraphyletic and thus CuZnSOD sequences that lay outside one of these identified monophyletic groups may not easily be classified and are annotated here in two shades of grey, corresponding with Table 1. Paraphyletic cytoplasmic localised MnSOD sequences (pale yellow shape, grey dashed line). Labels in blue denote sequences encoded by phylum Porifera, named by class. Vertebrate SOD sequences are denoted in bold font. Black numbers on branches indicate bootstrap support. Constructed based on edited alignment, 1000 bb and the WAG + R6 evolutionary model