Genome size, isolation source and number of secondary metabolite gene clusters. The phylogenetic tree shown is calculated on concatenated ribosomal proteins and rooted with Bifidobacterium bifidum as an outgroup. The two bar plots are presented with species in the same order as the phylogenetic tree, representing genome size in thousands of genes on the left, colored by habitat, and number of secondary metabolite gene clusters on the right. Any combinations of cluster types found together count independently, e.g. an NRPS/PKS hybrid would be counted once as an NRPS and once as a PKS. The colors corresponding to habitat type and secondary metabolite class are shown in the key below the bar plots.