Figure 2. Posterior bootstrap support values (p-values) for a ring model, tree model or equal probabilities for each of the sampled groups.

The p-values were calculated from 10,000 re-samplings with replacement and extracting the total number of times the tree model, ring model or when both were equally supported from the parsimony counts. Only in the case where all the double membrane prokaryotes as defined by Lake [2], or when all the proteobacteria were included, did a ring model better explain the data.