Rosenberg S M, Thulin C, Harris R S
Department of Biochemistry, University of Alberta, Edmonton, Canada.
Genetics. 1998 Apr;148(4):1559-66. doi: 10.1093/genetics/148.4.1559.
Major advances in understanding the molecular mechanism of recombination-dependent stationary-phase mutation in Escherichia coli occurred this past year. These advances are reviewed here, and we also present new evidence that the mutagenic state responsible is transient. We find that most stationary-phase mutants do not possess a heritable stationary-phase mutator phenotype, although a small proportion of heritable mutators was found previously. We outline similarities between this well-studied system and several recent examples of adaptive evolution associated with heritable mutator phenotype in a similarly small proportion of survivors of selection in nature and in the lab. We suggest the following: (1) Transient mutator states may also be a predominant source of adaptive mutations in these latter systems, the heritable mutators being a minority (Rosenberg 1997); (2) heritable mutators may sometimes be a product of, rather than the cause of, hypermutation that gives rise to adaptive mutations.
过去一年里，在理解大肠杆菌中依赖重组的稳定期突变分子机制方面取得了重大进展。本文对这些进展进行了综述，并且我们还提供了新的证据，表明相关的诱变状态是短暂的。我们发现，尽管之前发现了一小部分可遗传的诱变剂，但大多数稳定期突变体并不具有可遗传的稳定期诱变表型。我们概述了这个经过充分研究的系统与最近几个适应性进化实例之间的相似性，这些实例同样在自然界和实验室中经过选择的一小部分幸存者中，与可遗传的诱变表型相关。我们提出以下观点：（1）在这些后期系统中，短暂的诱变剂状态也可能是适应性突变的主要来源，可遗传的诱变剂只是少数（Rosenberg，1997年）；（2）可遗传的诱变剂有时可能是导致适应性突变的超突变的产物，而非原因。
