EVOPLANET

Organisms continually respond to environmental inputs. Such a plastic response results from an adaptive process, but the evolution of the complex underlying genetic architectures remains poorly understood. In this project, we will focus on the evolution of gene expression plasticity and in the evolution of the gene network structure. We propose a two-fold approach. In the one hand, we will set up a theoretical model coupling a gene network dynamic model (individual level), and a population genetic model (population model) making it possible to simulate the evolution of gene networks influenced by mutations, selection, and genetic drift. From this model, we will obtain theoretical predictions on the way networks respond to selection, depending on e.g. the variability of the environment. In another hand , we will validate these theoretical predictions, confronting them to experimental evolution results. We already have access to 18 lineages of a fungus, Zymoseptoria tritici, evolved in vitro for one year (> 500 generations) in stable or fluctuating temperature conditions. We will sequence the transcriptomes of these lineages at different time points during adaptation, and will compare the evolution of gene expressions and of the structure of underlying coexpression networks to simulation results. Our aim is to propose a theoretical framework able to predict important features of the evolution of complex genetic architectures depending on the stability of the environment, and to assess these predictions empirically.