[Mutagenic effect of the decay of 32p incorporated into mRNA]

The transcription of Escherichia coli lactose operon was induced and the conditions for 32P maximal incorporation into mRNA which is synthesized on this operon were made. The complex between mRNA and DNA has been fixed. The DNA complementary strand has been damaged with the 32P desintegration. The induction of mutants uncapable of lactose utilization has been observed. It is shown that the number of such mutants in the experiments with 32P and with the inducer is twice as much as in the cheek experiments with 32P only.