In one experimental system, several handles on the molecular mechanism of apparent
adaptive mutation have emerged. The system is reversion of a lac frame‐shift mutation in …

The sequences of adaptive reversions of a lac frameshift mutation in Escherichia coli
resemble DNA polymerase errors, and the adaptive reversions decrease in strains with an …

When bacterial cells are subjected to a strong selective pressure it often induces specific
mutations. Here a model is considered in which errors are introduced at random in one of …

Over the past 6 years an unexpected way of making mutations in bacteria has challenged
concepts of the genetic mechanisms behind evolution. Mechanistic studies of these so …

An important goal of molecular genetics is understanding in detail the muta tional process:
the mechanisms by which mutations occur spontaneously or are induced by mutagens, and …

Aspects of the molecular mechanism of “adaptive” mutation are emerging from one
experimental system: reversion of an Escherichia coli lac frameshift mutation carried on a …

Several microbial systems have been shown to yield advantageous mutations in slowly
growing or nongrowing cultures. In one assay system, the stationary-phase mutation …

Adaptive reversion of a lac-frameshift mutation in Escherichia coli appears to be due to DNA
polymerase errors, implying that DNA is being synthesized although the cells are not …

Major advances in understanding the molecular mechanism of recombination-dependent
stationary-phase mutation in Escherichia coli occurred this past year. These advances are …

A Lac-strain of Escherichia coli that reverts by the addition of a G to a GGGGGG sequence
was used to study the proliferation of mutators in a bacterial culture. Selection for the Lac+ …