Distribution of IS 6110 insertion sequence throughout the genome of M. tuberculosis Beijing strains. The located copies of IS6110 in NHN5, HM77, HM903, HM764, 990172, W4, N4 and CAM22 Beijing strains were plotted in H37Rv genome and represented in different concentric circles. IS6110 locations present either in all strains (red arrows) or with high frequency (black arrows) are indicated; ipl hot-spots are pointed with blue arrows. In this DNA plotter, the IS6110 locations of GC1237 , W and 210 Beijing strains  were also represented as IS6110 reference points of insertion. The unique insertion of IS6110 of GC1237  (within Rv2180c) is surrounded by a purple circle.