Figure 1.

Genome-wide transposon mutagenesis of S. Typhimurium. Circular plot showing gene content, distribution of required genes and insertion density along the S. Typhimurium chromosome. The outer scale is marked in megabases. Circular tracks range from 1 (outer track) to 6 (inner track). Track 1, all forward-strand genes (colour-coded according to function: dark blue, pathogenicity/adaptation; black, energy metabolism; red, information transfer; dark green, membranes/surface structures; cyan, degradation of macromolecules; purple, degradation of small molecules; yellow, central/intermediary metabolism; light blue, regulators; pink, phage/IS elements; orange, conserved hypothetical; pale green, unknown function; brown, pseudogenes.); track 2, all reverse-strand genes (colour-coded as for forward-strand genes); track 3, S. Typhimurium required genes (red); track 4, 56 genes required by S. Typhimurium, but not by S. Typhi (dark blue, see also Table 1); track 5, transposon insertion density; track 6, GC bias [(G − C)/(G + C)]), khaki indicates values >1; purple <1.