FIG. 1.

Polymorphic sites within the mdh (A) and hlyA (B) genes of V. cholerae isolates. (A) Polymorphic sites within unique mdh sequences. M793 represents the sixth-pandemic, seventh-pandemic, and U.S. Gulf Coast clones, M535 also represents M553, M557, also represents M558, and M559 also represents M560. (B) Polymorphic sites within the 1,038-bp segment of the hlyA gene. M793 represents the seventh-pandemic and U.S. Gulf Coast clones, M642 represents the sixth-pandemic clone, and M555 also represents M559 and M560. Numbering of the polymorphic sites (vertical format) are from the first position of the sequence segment. The position within the codon for each polymorphic site is shown below the sequences. Asterisks indicate polymorphic sites which are informative.