DNA sequences found at the boundaries of the four hot spots in ICEPdaSpa1, SXTMO10, and R391. Conserved DNA is shown in gray, ICEPdaSpa1-specific DNA is shown in green, SXT-specific DNA is shown in blue, and R391-specific DNA is shown in orange. Nucleotide differences in the conserved DNA are indicated in black. The box represents the stop codon in traA.