Variation in depth of coverage of the sequenced isolates, based on read alignments of the seven sequenced strains against the N16961 reference genome. Chromosome 1 (A) and chromosome 2 (B) are shown. The depth of coverage of 1000 base pair windows of 150x average coverage subsamples of the DR1 (outermost circle), H1*, H2*, H3, N16961*, O395*, and DB_2002 (innermost circle) isolates is displayed. Regions at low depth of coverage (<12x) are shown in red, while regions at high depth of coverage (>240x) are shown in blue. The depth of coverage in each window is displayed using the Circos tool . Genomic islands as defined in  and the superintegron region as defined in  are shown.