Transposon Tn1 intra-molecular transposition.

A system for the direct selection of intra- and inter-molecular transposition events has been used to show that intra-molecular transposition of Tn1 generates deletions and inversions and requires the tnpA but not the tnpR gene product, as predicted by current models of transposition. Intra-molecular Tn1 transposition is much less limited by 'transposition immunity' than inter-molecular transposition, and occurs at frequencies comparable to those for inter-molecular transposition. The selection system, which uses the bacteriophage lambda cI- PR region as a target can be used to select, quantify, and characterize any spontaneous or induced mutations.