Maps of Buchnera Mp USDA, W106, F009, and G002 strains. The outside green wavy line is the AT frequency across the Buchnera Mp USDA genome. The three grey circles associated with the green wavy line mark 0, 0.5 and 1.0 AT frequency (from inside to outside). AT frequency was calculated using a 100 bp sliding-window with a window step of 10 bp. The red blocks on the two red circles are the annotated protein coding genes of the BuMp_USDA genome; the blue bars between the two red circles mark tRNAs and rRNAs. The three innermost orange circles represent the W106, F009 and G002 genomes with the orange bars on these circles indicating synonymous substitutions and the purple bars indicating nonsynonymous substitutions relative to BuMP_USDA.