Universal Laws in Phenotypic Changes through Adaptation and Evolution

Abstract

A macroscopic theory for biological adaptation and evolution is presented. By constraint on steady-growth and robustness of a cellular state, adaptive changes in high-dimensional phenotypic state are constrained to a low-dimensional space, which leads to universal laws on concentration changes across all intracellular components and the cellular growth rate. This universal relation is confirmed in numerical simulations of a simple cell model as well as by bacterial experiments. The present theory is extended to evolution, to show that the concentration changes induced by environmental changes are proportionally reduced across different components of a cell by evolution, which is akin to the Le Chatelier thermodynamics principle. Finally, with the aid of a fluctuation–response relationship, this proportionality is shown to also hold between fluctuations caused by genetic changes and those caused by noise. Overall, these results suggest a thermodynamic-like formulation of cellular systems.