FIG. 2.

Southern analysis of CDC0826-83 demonstrates that the observed variation is not a PCR artifact but encoded on the chromosome. The bacterial (Bact.) probe recognizes most bacterial 16S rRNA genes and each of the 16S rRNA gene copies in Aeromonas. Probe 230-232A anneals only to allele 1 from CDC0862-83, and probe 230-232B anneals to alleles 2 through 6. The hybridization patterns of the membrane probed with 230-232A show two bands hybridizing with the genomic DNA digested with PstI, PvuII, or SmaI, indicating that two copies of this polymorphism characteristic of allele 1 are present in the genome of CDC0862-83.