The evolutionary significance of stress-induced mutagenesis was evaluated by studying
mutagenesis in aging colonies (MAC) of Escherichia coli natural isolates. A large fraction of …

In natural habitats, bacteria spend most of their time in some form of growth arrest. Little is
known about deleterious mutations in such stages, and consequently there is limited …

Mutagenesis is often increased in bacterial populations as a consequence of stress-induced
genetic pathways. Analysis of the molecular mechanisms involved suggests that …

Evolutionary theory assumed that mutations occur constantly, gradually, and randomly over
time. This formulation from the “modern synthesis” of the 1930s was embraced decades …

Comparative biochemistry demonstrates that the metabolites, complex biochemical
networks, enzymes and regulatory mechanisms essential to all living cells are conserved in …

Evolution by natural selection is driven by the continuous generation of adaptive mutations.
We measured the genomic mutation rate that generates beneficial mutations and their …

Most types of antibiotic resistance impose a biological cost on bacterial fitness. These costs
can be compensated, usually without loss of resistance, by second-site mutations during the …

A fraction of a genetically homogeneous microbial population may survive exposure to
stress such as antibiotic treatment. Unlike resistant mutants, cells regrown from such …

Increased mutation rates under stress allow bacterial populations to adapt rapidly to
stressors, including antibiotics. Here we evaluate existing models for the evolution of stress …

To estimate the number and diversity of beneficial mutations, we experimentally evolved 115
populations of Escherichia coli to 42.2° C for 2000 generations and sequenced one genome …