Box plot summarizing correlations between tCAI and dCAI for eight major bacterial phyla and fungi. The group 'Other bacteria' comprises a number of minor bacterial phyla (Aquificae, Chloroflexi, Fusobacteria, Planctomycetes, Acidobacteria, and Thermotogae) that could not meaningfully be included in any of the other categories. The box plot illustrates the median correlations of each group as well as upper and lower quartiles. The numbers on the right side of the figure specifies the number of genomes included in each group. dCAI, dominant codon adaptation index; tCAI, translational codon adaptation index.