Department of Ecology & Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA.
Department of Ecology & Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA.
Cell Rep. 2018 Oct 2;25(1):249-258. doi: 10.1016/j.celrep.2018.09.008.
All biological populations are to a greater or lesser degree evolvable, but the forces that shape evolvability, especially the evolution of evolvability as an adaptive response to pressure to evolve rapidly, are a source of controversy. One determinant of evolvability is the set of possible mutations available to a genotype, or "mutational neighborhood." A benign (instead of deleterious) mutational neighborhood can enhance evolvability. Whether selection for evolvability itself can result in a more benign mutational neighborhood remains an open question. We document the evolution of increased evolvability in a fluctuating environment despite using a regime that precludes, by design, the adaptive evolution of evolvability. Instead, a benign mutational neighborhood arises as a byproduct of transiently elevated error rates via a mechanism that we call emergent evolutionary capacitance. This is evolutionary capacitance similar to that seen in a model system for capacitance, the yeast prion [PSI+], but without a capacitor.
所有生物种群在一定程度上都是可进化的，但塑造进化能力的力量，尤其是进化能力作为对快速进化压力的适应性反应的进化，是一个有争议的来源。进化能力的一个决定因素是基因型或“突变体邻域”中可用的可能突变的集合。良性（而不是有害）的突变体邻域可以增强进化能力。选择进化能力本身是否会导致更良性的突变体邻域仍然是一个悬而未决的问题。我们记录了在波动环境中进化能力的增强，尽管使用的是一种通过设计排除进化能力适应性进化的机制。相反，良性的突变体邻域是通过我们称之为突现进化电容的机制，通过暂时提高错误率而产生的副作用。这是类似于酵母朊病毒[PSI+]中电容模型系统中看到的进化电容，但没有电容器。
