title: Global relationships in fluctuation and response in adaptive evolution.
abstract: Cells change their internal state to adapt to environmental changes, and evolve in response to the new conditions. The phenotype changes first via adaptation in response to environmental changes, and then through mutational changes in the genomic sequence, followed by selection in evolution. Here, we analysed simulated adaptive evolution using a simple cell model consisting of thousands of intracellular components, and found that the changes in their concentrations by adaptation are proportional to those by evolution across all the components, where the proportion coefficient between the two agreed well with the change in the growth rate of a cell. Furthermore, we demonstrate that the phenotypic variance in concentrations of cellular components due to (non-genetic) noise and to genomic alternations is proportional across all components. This implies that the specific phenotypes that are highly evolvable were already given by non-genetic fluctuations. These global relationships in cellular states were also supported by phenomenological theory based on steady reproduction and transcriptome analysis of laboratory evolution in Escherichia coli. These findings demonstrate that a possible evolutionary change in phenotypic state is highly restricted. Our results provide a basis for the development of a quantitative theory of plasticity and robustness in phenotypic evolution.
authors.affiliation: Quantitative Biology Center, RIKEN, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan chikara.furusawa@riken.jp.
authors.forename: Chikara
authors.initials: C
authors.lastname: Furusawa
authors.affiliation: Research Center for Complex Systems Biology, University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan kaneko@complex.c.u-tokyo.ac.jp.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Kaneko
mesh_terms: D000222:Adaptation, Physiological; D019020:Directed Molecular Evolution; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008954:Models, Biological; D014158:Transcription, Genetic
keywords: adaptive evolution; computer simulation; experimental evolution; global relationship