Fig. 4

Distribution of mariner insertions identified in the A. pleuropneumoniae and P. multocida genomes. TraDIS reads for the respective pooled libraries were mapped to A the complete genome of A. pleuropneumoniae MIDG2331 (accession number LN908249); and D the draft genome (pseudochromosome) of P. multocida MIDG3277 (accession number ERZ681052). Each spike plotted around the chromosome represents a single insertion site, with the length of each spike proportional to the number of mapped sequence reads from that insertion site. A total of 78,638 unique insertion sites were identified in the A. pleuropneumoniae MIDG2331 library, and 147,613 in the P. multocida MIDG3277 library. In the MIDG3277 dataset, there were several insertion sites with large numbers of mapped reads. To enable insertions with fewer reads to be seen clearly, read coverage has been capped to a maximum of 50,000 in D (the true maximum coverage at an insertion site was 136,032 reads). The pseudochromosome of P. multocida MIDG3277 was assembled based on ordering of the draft sequence contigs following alignment, using NUCmer 4.0 (43), with the complete genome of P. multocida Pm70, as shown in C. Arrows indicate the position and orientation of the contigs. Red blocks indicate matches in the same orientation, blue blocks indicate matches in the reverse orientation. Plots of the cumulative insertion counts across the MIDG2331 chromosome B and MIDG3277 pseudochromosome E are shown in red, with a dotted line indicating the expected relationship for uniformly distributed insertions. Both libraries deviate from this, with a bias towards insertions close to the origin of replication, but insertions are found across the genome in both libraries