The left panel shows genomic rearrangements of three spontaneous colony variants of B. petrii. Genomic DNA of B. petrii wild type (1), variant f (2), variant g (3) and variant k (4) was cut with Bcu I and separated by pulsed field electrophoresis. The red arrows indicate three bands which are missing in the three variants as compared to the wild type. The right panel shows a representative pulsed field gel of wild type B. bronchiseptica PS2 (lane 1), B. petrii (lane 2) and the two GI3::tetR transconjugants of B. bronchiseptica (lanes 3,4) after digestion with Bcu I. The red arrows indicate the additional bands present in the transconjugants as compared to B. bronchiseptica wild type.