Fig. 4. MspI digestion of a 617-bp product amplified from plasmid DNA extracted from recombinant clones containing the imi1, imi2, and imi3 genes cloned from CDC Teal. The three genes could be distinguished on the basis of polymorphic restriction patterns following digestion of the 617-bp amplicon. The 617-bp sequence of imi1 lacks an MspI digestion site (Lanes 2, 9, 10), whereas imi2 possesses four restriction sites, resulting in fragments 63, 75, 171, and 223 bp in length (Lanes 3, 4, 8). The 617-bp sequence of imi3 possesses a single restriction site, resulting in fragments 446 and 171 bp in length (Lanes 1, 5, 6, 7). Identical restriction patterns where noted in all resistant lines (Data not shown).