TABLE 3.
Structural differences between previously identified class 1 integrons and those isolated in this study
| Characteristics of previously described class 1 integrons | Characteristics of Lake Yerbury class 1 integrons |
|---|---|
| IRi present | IRi absent in two examplesa |
| IRt present or evidence of deletion-induced loss | IRt not present |
| Partial or complete suite of Tn402-like tni genes or evidence of deletion-induced loss | No Tn402-like tni genes or divergent genes in opposite orientation |
| Insertion in or near a res site | No res site at insertion point |
| 3′-CS commonly present | No 3′-CS |
| Cassette arrays common; most contain antibiotic resistance genes | No cassettes or no resistance genes in cassette array |
a
Also absent are TnpA binding domains i1 and i2 (see text and reference 20).