Fig 2. Relative fequency of genomes encoding for hemerythrin domain homologues across a species phylogeny.

Phylogenetic tree based on a small subunit rRNA guide tree containing only completely sequenced species. Bacterial and archaeal species are collapsed on the phylum and group level. Eukaryotic species are collapsed together. n: number of species contained within each collapsed branch. The red bar is proportional to the number of species with at least one hemerythrin sequence in each collapsed branch. The total number of genomes with at least one O2-binding hemerytrhin is indicated by a red number next to the bar.