The role of transient hypermutators in adaptive mutation in Escherichia coli
| Autor: | Patricia L. Foster, William A. Rosche |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Genetics
Mutation rate education.field_of_study Multidisciplinary Period (gene) Population Somatic hypermutation lac operon Gene Expression Regulation Bacterial Biological Sciences Biology medicine.disease_cause Molecular biology Lac Operon Adaptive mutation Mutation Mutation (genetic algorithm) Escherichia coli medicine education Genome Bacterial |
| Zdroj: | Proceedings of the National Academy of Sciences. 96:6862-6867 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.96.12.6862 |
| Popis: | Microbial populations under nonlethal selection can give rise to mutations that relieve the selective pressure, a phenomenon that has come to be called “adaptive mutation.” One explanation for adaptive mutation is that a small proportion of the cells experience a period of transient hypermutation, and that these hypermutators account for the mutations that appear. The experiments reported here investigated the contribution that hypermutators make to the mutations occurring in a Lac − strain of Escherichia coli during selection for lactose utilization. A broad mutational screen, loss of motility, was used to compare the frequency of nonselected mutations in starved Lac − cells, in Lac + revertants, and in Lac + revertants carrying yet another nonselected mutation. These frequencies allowed us to calculate that the hypermutating subpopulation makes up ≈0.06% of the population and that its mutation rate is elevated ≈200-fold. From these numbers we conclude that the hypermutators are responsible for nearly all multiple mutations but produce only ≈10% of the adaptive Lac + mutations. |
| Databáze: | OpenAIRE |
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