Fig. 1.

Distribution of circadian clock proteins. a, b Shown are the mean sequence similarites of each protein for each genus that contains a KaiC homolog from Synechococcus 7942. The genera are sorted by their group and KaiC similarity. The number in parenthesis represents the number of individual genomes per genus. a shows the mean similarities for the circadian clock proteins of Synechococcus 7942. b shows the mean similarities for the circadian clock proteins of Synechocystis 6803. The four taxonomic main groups are highlighted: Cyanobacteria (Green), Proteobacteria (Blue), Archaea (Red), Other (Grey). c shows the number of homologs for each protein in each cyanobacterium. Copy numbers higher than five were condensed. Cyanobacterial strains with true circadian clocks [8, 78–80, 106, 143–148] are highlighted with a yellow hexagon and the strain with hourglass like timing mechanism [92] with a green triangle. We could not find references for all strains, however, we identified strains with circadian rhythms, which are not listed here as their genomes are still not fully assembled