Adaptive Mutation and Slow-Growing Revertants of an Escherichia coli lacZ Amber Mutant

Adaptive mutation and slow-growing revertants of an Escherichia coli lacZ amber mutant.

We have studied revertants, selected on lactose minimal agar medium, of the Escherichia coli lacZam strain that was first used by Cairns and his colleagues to demonstrate the phenomenon of "adaptive mutation." We have found, by performing appropriate reconstruction studies, that most of the late-arising Lac+ revertants of this lac amber strain (appearing as colonies in 3-5 days) are slow-growin...

Adaptive mutation in Escherichia coli.

In 1988 John Cairns, Julie Overbaugh, and Stephan Miller published a paper entitled “The origin of mutants,” in which they suggested that bacteria could choose which mutations to make (11). Shortly thereafter, Cairns and I began collaborating on a National Science Foundation-funded project to investigate the genetic basis of what was popularly called “directed mutation” (although at the time we...

Characterization of a temperature-sensitive Escherichia coli mutant and revertants with altered seryl-tRNA synthetase activity.

A mutation in the structural gene coding for seryl-tRNA synthetase in temperature-sensitive Escherichia coli K28 has been reported to alter the level of enzyme expression at high temperature (R. J. Hill and W. Konigsberg, J. Bacteriol. 141:1163-1169, 1980). We identified this mutation as a C-->T transition in the first base of codon 386, resulting in a replacement of histidine by tyrosine. The ...

Identification of an amber uvrC mutant in Escherichia coli K-12.

Rebuttal: adaptive mutation in Escherichia coli (Foster).

If mutations arose in nongrowing cells, as proposed in Foster’s paper (1), then stress-induced mutagenesis would seem inescapable. The plated population certainly grows very little. However, no evidence is provided that reversion occurs in this population and no effort is made to counter evidence to the contrary (see below)—that mutations actually arise in cells growing under selection within d...