Levin B R
Department of Zoology, University of Massachusetts, Amherst 01003.
Philos Trans R Soc Lond B Biol Sci. 1988 Jul 6;319(1196):459-72. doi: 10.1098/rstb.1988.0059.
There are many situations in which the direction and intensity of natural selection in bacterial populations will depend on the relative frequencies of genotypes. In some cases, this selection will favour rare genotypes and result in the maintenance of genetic variability; this is termed stabilizing frequency-dependent selection. In other cases, selection will only favour genotypes when they are common. Rare types cannot invade and genetic variability will not be maintained; this is known as disruptive frequency-dependent selection. Phage-mediated selection for bacteria with novel restriction-modification systems is frequency-dependent and stabilizing. In mass culture, selection for the production of toxins and allelopathic agents is likely to be frequency-dependent but disruptive. This also occurs in selection favouring genes and transposable elements that cause mutations. Here I review the results of theoretical and experimental studies of stabilizing and disruptive frequency-dependent selection in bacterial populations, and speculate on the importance of this kind of selection in the adaptation and evolution of these organisms and their accessory elements (plasmid, phage and transposons).
在许多情况下，细菌群体中自然选择的方向和强度将取决于基因型的相对频率。在某些情况下，这种选择将有利于稀有基因型，并导致遗传变异性的维持；这被称为稳定频率依赖性选择。在其他情况下，选择仅在基因型常见时才有利于它们。稀有类型无法入侵，遗传变异性也无法维持；这被称为干扰频率依赖性选择。噬菌体介导的对具有新型限制 - 修饰系统的细菌的选择是频率依赖性且稳定的。在大规模培养中，对毒素和化感物质产生的选择可能是频率依赖性但具有干扰性的。这在有利于导致突变的基因和转座元件的选择中也会发生。在这里，我回顾了细菌群体中稳定和干扰频率依赖性选择的理论和实验研究结果，并推测这种选择在这些生物体及其附属元件（质粒、噬菌体和转座子）的适应和进化中的重要性。
