Foster P L
Department of Biology, Indiana University, Bloomington 47405, USA.
Annu Rev Genet. 1999;33:57-88. doi: 10.1146/annurev.genet.33.1.57.
A decade of research on adaptive mutation has revealed a plethora of mutagenic mechanisms that may be important in evolution. The DNA synthesis associated with recombination could be an important source of spontaneous mutation in cells that are not proliferating. The movement of insertion elements can be responsive to environmental conditions. Insertion elements not only activate and inactivate genes, they also provide sequence homology that allows large-scale genomic rearrangements. Some conjugative plasmids can recombine with their host's chromosome, and may acquire chromosomal genes that could then spread through the population and even to other species. Finally, a subpopulation of transient hypermutators could be a source of multiple variant alleles, providing a mechanism for rapid evolution under adverse conditions.
对适应性突变的十年研究揭示了大量可能在进化中起重要作用的诱变机制。与重组相关的DNA合成可能是未增殖细胞中自发突变的重要来源。插入元件的移动可以对环境条件作出反应。插入元件不仅能激活和失活基因，还能提供序列同源性，从而允许大规模的基因组重排。一些接合质粒可以与其宿主染色体重组，并可能获得随后可在群体中传播甚至传播到其他物种的染色体基因。最后，瞬时高突变体亚群可能是多个变异等位基因的来源，为不利条件下的快速进化提供了一种机制。
