Postexcision transposition of the transposon Tn10 in Escherichia coli K12.

An experimental analysis of the fate of transposon Tn10 after excision from a proA::Tn10 site localized on the plasmid F' leads to the conclusions: 1. The precise excision is a progressive process. Its probability is estimated per time unit. 2. An excised Tn10 is always integrated into a different genetic locus. 2. An excised Tn10 is always integrated into a different genetic locus. 3. The kinetics of postexcision transposition are sometimes very slow. The excised transposon is inherited in one cell line in spite of cell multiplication. 4. The processes of excision and secondary insertion have no absolute requirement for the recA+ genotype but they are strongly enhanced in recA+ cells. 5. The kinetics of postexcision transposition are strongly dependent on the genetic site from which the transposon was excised. 6. The probability of postexcision transposition is fully determined by the probability of excision and depends on the genotype of the host and many other factors.