Comparison of the O37 wb* region with the O1 wbe and O139 wbf regions. The genetic organization of the wb* region of the O37 strain is compared to the genetic organizations reported previously (49) for the O1 and O139 strains. The O139, O1, and O37 regions are 35, 22, and 27 kb long, respectively. The ORFs and the directions of transcription are indicated by the arrows, and the common ORFs in the three serogroups are indicated by the same types of arrows. The common junction genes (gmhD and rjg) of the three serogroups are indicated by solid arrows. While the left junction is at gmhD in all three serogroups, the right junction in O37 is different from the right junction in O139. The O1 right junction genes, wbeV through rjg, are conserved in the O37 wb* region.