Fig 4. Presence/absence matrix of the different protein domain architectures in bacterial, archaeal and eukaryotic species.

Protein domain architectures were obtained as specified in the Methods section. Defined Pfam-A domains are represented by boxes. Only architectures where three or more protein sequences were identified are depicted here. The size of the boxes representing each domian and spacing between contiguous boxes are arbitrary. Hemerythrin domain overlapping other protein domains is represented as half-filled blue boxes.