Figure 3.

Consequences of inversions at different locations in a prokaryotic chromosome. The green arrows indicate sites of recombination. The black arrows represent a sense strand of a gene. Note that if the sense strand is lying on the leading DNA strand, the direction of transcription of the gene is the same as the direction of replication-fork movement. (a) A symmetrical inversion encompassing the origin of replication. After the inversion, the distances to the origin and the locations of the genes do not change with respect to the leading and lagging DNA strands. (b) The inverted region encompasses the origin but the origin is not located in the center of this region. As a result, the lengths of replichores change and the distances of the noninverted genes to the origin change, although the locations of the genes do not change with respect to the leading and lagging DNA strands. (c) An inversion within a replichore. The locations of genes within the inverted sequence change with respect to the leading and lagging DNA strands. Furthermore, genes located away from the center of the inverted region change their distance from the origin.