Figure 4.

The ability of an organism to live in multiple habitats is the feature most correlated with the extent of codon usage bias. The 518 prokaryotes were divided into two groups - organisms who each live in a specialized environment and organisms who each live in multiple habitats - and the CAI_ave values of the different groups were compared. CAI_ave is indicated as 'Average CAI'. CAI: Codon Adaptation Index; GC: genome content.