Codon adaptation index is high in P. aeruginosa and independent of gene expression. A) Histogram of codon adaptation index (CAI) and B) gene expression in P. aeruginosa. C) Gene expression data is only weakly correlated with the codon adaptation index in PAO1 (R = 0.135). Color indicates the density of data points at the coordinates indicated by the spots ranging from blue (single data point) to deep red (many). D) Core genes in PAO1 show generally high CAI values, while the accessory genome is significantly less adapted. Boxplots indicate 0.25 and 0.75 quantiles and the median (red line) with notches giving an estimate for the variance of the median. The green dashed line indicates the median dN for all genes.