Fig. 5
Selection acts in proportion to mRNA abundance to decrease codon biosynthetic cost and increase codon translational efficiency in Escherichia coli. a There is a negative correlation between selection acting on codon biosynthetic cost (Sc) and mRNA abundance. The linear line of best fit (shown here on a log scale) has an R2 value of 0.18. b There is a positive correlation between selection acting to increase codon translational efficiency (St) and gene expression. The linear line of best fit (shown here on a log scale) has an R2 value of 0.13. Each point has been set to an opacity of 20% so density can be judged