Unité Mixte de Recherche 1137 (IAME-INSERM) Paris, France.
Front Genet. 2015 Mar 11;6:99. doi: 10.3389/fgene.2015.00099. eCollection 2015.
One of the most recurrent observations after two decades of microbial evolution experiments regards the dynamics of fitness change. In a given environment, low-fitness genotypes are recurrently observed to adapt faster than their more fit counterparts. Since adaptation is the main macroscopic outcome of Darwinian evolution, studying its patterns of change could potentially provide insight into key issues of evolutionary theory, from fixation dynamics to the genetic architecture of organisms. Here, we re-analyze several published datasets from experimental evolution with microbes and show that, despite large differences in the origin of the data, a pattern of inverse dependence of adaptability with fitness clearly emerges. In quantitative terms, it is remarkable to observe little if any degree of idiosyncrasy across systems as diverse as virus, bacteria and yeast. The universality of this phenomenon suggests that its emergence might be understood from general principles, giving rise to the exciting prospect that evolution might be statistically predictable at the macroscopic level. We discuss these possibilities in the light of the various theories of adaptation that have been proposed and delineate future directions of research.
在微生物进化实验进行了二十年之后，人们最常观察到的一个现象是适应度变化的动态。在给定的环境中，低适应度基因型被反复观察到比它们更适应的同类适应得更快。由于适应是达尔文进化的主要宏观结果，因此研究其变化模式可能为进化理论的关键问题提供一些见解，从固定动力学到生物体的遗传结构。在这里，我们重新分析了来自微生物实验进化的几个已发表数据集，并表明，尽管数据的起源存在很大差异，但适应性与适应度的反比关系模式明显出现。从数量上看，令人惊讶的是，在病毒、细菌和酵母等如此多样化的系统中，几乎没有任何程度的特殊性。这种现象的普遍性表明，它的出现可能可以用一般原理来理解，从而产生了一个令人兴奋的前景，即进化在宏观层面上可能具有统计学可预测性。我们根据已经提出的各种适应理论来讨论这些可能性，并描绘出未来的研究方向。
