Figure 2.

Relationship between codon adaptation indices (CAI) of GFP gene variants and doubling time of (A) C. crescentus, (B) P. aeruginosa, and (C) E. coli. A significant positive association between CAI and fitness was observed in E. coli (P = 0.03; r² =0.30) on induction of GFP but no significant relationship was observed when GFP was not expressed (P = 0.07). There is no significant relationship between the CAI of GFP genes and doubling times in P. aeruginosa under induced (P = 0.48) and not induced (P = 0.40) conditions. Similarly, in C. crescentus, CAI is not significantly related to doubling times under induced (P = 0.12) and not induced (P = 0.37) conditions. Error bars designate the SEM, which represents how well the sample mean represents the corresponding population mean.