Elevated mutation rate in mutT bacteria during starvation: evidence for DNA turnover?

The rate of appearance of prototrophic revertants when Escherichia coli tyrA14 (ochre) or trpA23 bacteria were incubated on plates lacking the required amino acid was greatly elevated when the organisms also carried a mutT mutation. One possible explanation for this result is that the amount of DNA replication or turnover under these conditions is much greater than has been previously recognized.