Extended Data Fig. 6:

Rho shapes amino acid usage in Bacilli. Related to Fig. 3. Distribution of relative amino acid usage in Bacilli species separated by the presence or absence of a rho homolog⁴⁰. Relative amino acid usage is shown for amino acid pairs with a strong (≥2) BLOSUM-62 substitution score⁴⁶, where amino acid substitution requires a change in purine content in the nucleotide sequence without necessitating a change in GC content. Bacilli species shown have similar GC content (35–45%). n = 204 species (111 Rho, 93 no rho). Boxplots show median, 25^th, 75^th percentiles. Underlined residue indicates position where purine content differs between amino acids. R, purine; Y, pyrimidine; N, any nucleotide. P-values from one-sided Mann-Whitney U tests. d indicates Cohen’s d effect size (Methods).