TABLE 1.

Transposon Tn21 and the mobile elements it contains

Element	Coordinates	Size (bp)
Tn21	1–19671	19,671
In2	4040a–15038	10,999
aadA1 cassetteb	5395–6250	856
IS1326	8276–10719, 12333–12360c	2,470
IS1353	10720–12332	1,612

^aDuplication of 5 bp due to insertion of In2; coordinates 4035 to 4039 and 15039 to 15543. 

^bThe cassette is located within In2 but is independently mobile. 

^cThe sequence of IS1326 is interrupted by the insertion of IS1353, which creates a 2-bp target site duplication.