Evidence that selected amplification of a bacterial lac frameshift allele stimulates Lac(+) reversion (adaptive mutation) with or without general hypermutability.

Abstract excerpt

In the genetic system of Cairns and Foster, a nongrowing population of an E. coli lac frameshift mutant appears to specifically accumulate Lac(+) revertants when starved on medium including lactose (adaptive mutation). This behavior has been attributed to stress-induced general mutagenesis in a subpopulation of starved cells (the hypermutable state model). We have suggested that, on the contrary, stress has no...

Topics

• Bacterial Proteins
• Escherichia coli
• Frameshift Mutation
• Gene Amplification
• Genotype
• Lac Operon
• Lactose
• Serine Endopeptidases
• Time Factors