BACKGROUND: An important question is whether evolution favors properties such as mutational robustness or evolvability that do not directly benefit any individual, but can influence the course of future evolution. Functionally similar proteins can differ substantially in their robustness to mutations and capacity to evolve new functions, but it has remained unclear whether any of these differences might be due to evolutionary selection for these properties.
RESULTS: Here we use laboratory experiments to demonstrate that evolution favors protein mutational robustness if the evolving population is sufficiently large. We neutrally evolve cytochrome P450 proteins under identical selection pressures and mutation rates in populations of different sizes, and show that proteins from the larger and thus more polymorphic population tend towards higher mutational robustness. Proteins from the larger population also evolve greater stability, a biophysical property that is known to enhance both mutational robustness and evolvability. The excess mutational robustness and stability is well described by existing mathematical theories, and can be quantitatively related to the way that the proteins occupy their neutral network.
CONCLUSIONS: Our work is the first experimental demonstration of the general tendency of evolution to favor mutational robustness and protein stability in highly polymorphic populations. We suggest that this phenomenon may contribute to the mutational robustness and evolvability of viruses and bacteria that exist in large populations.
Modeling Protein Evolution via Generative Inference From Monte Carlo Chains to Population Genetics
Politecnico di Torino（都灵理工大学）；Sorbonne Université（索邦大学）；CNRS（法国国家科学研究中心）；Laboratory of Computational and Quantitative Biology（计算与定量生物学实验室）；École Normale Supérieure（巴黎高等师范学院）；PSL Université（巴黎文理研究大学）；Université de Paris（巴黎大学）；The James Franck Institute（詹姆斯·弗兰克研究所）；The University of Chicago（芝加哥大学）；Department of Physics, The University of Chicago（芝加哥大学物理系）；INFN, Sezione di Torino（意大利国家核物理研究所都灵分部）；Italian Institute for Genomic Medicine, IRCCS Candiolo（意大利基因组医学研究所坎迪奥洛医院）；Dipartimento di Fisica, Sapienza Università di Roma（罗马大学物理系）
