Figure 4.

Metacaspase phylogenetic tree. Maximum likelihood inference of the p10 and p20 catalytic cores of metacaspases using the LG substitution model with an estimated proportion of invariable sites and four substitution rate categories. Caspases and paracaspases are included as outgroups (purple and yellow branches, respectively). Expected Likelihood Weights (1000 replications) greater than 75% are indicated as circles at the nodes. Green branches denote eukaryotic metacaspase sequences, blue prokaryotic metacaspase sequences and red putative and known viral metacaspase sequences (see Supplementary Data set S4 for abbreviation definitions). Scale bar represents the number of inferred amino acid substitutions per site.