Barnett Michael, Meister Lena, Rainey Paul B
Department of Microbial Population Biology, Max Planck Institute for Evolutionary Biology, Plön, Germany.
Laboratory of Biophysics and Evolution, CBI, ESPCI Paris, Université PSL, CNRS, Paris, France.
Science. 2025 Feb 21;387(6736):eadr2756. doi: 10.1126/science.adr2756.
Evolvability-the capacity to generate adaptive variation-is a trait that can itself evolve through natural selection. However, the idea that mutation can become biased toward adaptive outcomes remains controversial. In this work, we report the evolution of enhanced evolvability through localized hypermutation in experimental populations of bacteria. The evolved mechanism is analogous to the mutation-prone sequences of contingency loci observed in pathogenic bacteria. Central to this outcome was a lineage-level selection process, where success depended on the capacity to evolve between two phenotypic states. Subsequent evolution showed that the hypermutable locus is itself evolvable with respect to alterations in the frequency of environmental change. Lineages with localized hypermutability were more likely to acquire additional adaptive mutations, revealing an unanticipated benefit.
可进化性——产生适应性变异的能力——是一种自身能够通过自然选择进化的特性。然而，突变可能偏向适应性结果这一观点仍存在争议。在这项研究中，我们报告了在细菌实验群体中通过局部高突变实现增强可进化性的进化过程。进化出的机制类似于在病原菌中观察到的应急位点的易突变序列。这一结果的核心是一个谱系水平的选择过程，成功与否取决于在两种表型状态之间进化的能力。后续进化表明，高突变位点本身会随着环境变化频率的改变而进化。具有局部高突变性的谱系更有可能获得额外的适应性突变，揭示了一种意想不到的益处。
