Fig. 3

a Genes duplicated in the E. coli strain 042. The X axis corresponds to the linear map of the chromosome. Each group of spots connected by a horizontal dashed line corresponds to a single gene duplicated in different positions on the chromosome. The different spots indicate the map positions of the different copies of the gene. Point shapes represent the strand on which a protein is encoded: filled circle for (+) strand and circle for (−) strand. Numbers correspond to the different duplicated genes, which have been numbered by their order starting from the origin of the chromosomal map. Genes numbered 2 to 5, 10 to 12, 77 to 80 (black closed and open circles) correspond to transposases. Colors and vertical bars define the three main regions that contain duplicated genes. Duplications 1, 9 and 13 are not shown because both repeated copies map to the pAA plasmid (not shown in the figure). Duplications 4 to 8 contain one copy in the chromosome (shown) and the other in the plasmid (not shown). b Details of regions 1 to 3, showing duplicated genes (labeled in black). To show inversion, both copies of region 2 are shown. Genes labeled in green correspond to the flu yeeR gene cluster. Thin gray arrows correspond to the in silico operon prediction. The figure was generated using Easyfig [40]. See Additional file 1: Table S3 for the function of each duplicated gene