Figure 1.

Biotin biosynthesis. The biotin biosynthesis subsystem contains 9 functional roles (Supplementary Table 2) and 10 metabolites. Functional roles are represented by rectangles. The major biosynthesis routes are colored green, alternative routes are blue, salvage routes are red, and known transporters are yellow. Metabolites are represented by circles, and yellow circles represent metabolites that can be salvaged from the environment in some cases. Only the core metabolites of the biosynthesis pathway are listed. Each bar graph represents the percentage of organisms in each phylum that contain the functional role.