Figure 4
From: Preferred and avoided codon pairs in three domains of life

The effect of genome size on the fraction of biased codon pairs. A – the percentage of biased codon pairs in full bacterial genomes. B – the percentage of biased codon pairs in standardized bacterial genomes. Green diamonds – Aeropyrum pernix, Methanopyrus kandleri and Nanoarchaeum equitans. Red diamonds – Buchnera aphidicola and Candidatus blochmannia pensilvanicus.