RFLP analysis of EcoRI, EcoRV, and MunI enzyme-digested genomic DNA from various mutants. Restriction fragments were blotted and hybridized with [α-33P]ATP-labeled IS66, IS21, repeat1, and repeat2 probes. Lane A, MSR-1A; lane L, MSR-1L; lane K, MSR-1K; lane B, MSR-1B; lanes A1, A2, A3, and A4, type A mutants; lanes B1, B2, B3, and B4, type B mutants.