[Initial characteristics and isolation of bacterial mutants with altered ability to transpose Tn9]

The method allowing the induction of bacterial mutations affecting Tn9 transposition from the bacteriophage genome to the Escherichia coli chromosome is described. Neither impaired ability of cells to adsorb bacteriophages, nor phage DNA degradation in the mutant cells were observed in the transposition-defective mutants isolated by the method. This led us to the conclusion that the isolated mutants were indeed defective in the transposition of Tn9.