Dresden 2026 – scientific programme

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BP: Fachverband Biologische Physik

BP 21: Focus Session: Sequence Spaces, Populations and Evolution

BP 21.5: Talk

Wednesday, March 11, 2026, 16:45–17:00, HÜL/S386

Adaptive Response of Quantitative Traits to a Moving Fitness Landscape — •Sakshi Pahujani, Yuna Zhang, Markus G. Stetter, and Joachim Krug — University of Cologne, Cologne, Germany

Phenotypic adaptation to long term persistent changes in the environment is typically studied using moving optimum models which consider a fitness landscape traversing the phenotypic space over time. Invoking the strong-selection-weak-mutation regime, we study adaptation as a walk towards the moving fitness optimum described by a continuous-state-discrete-time stochastic process. In this framework, at a critical speed of the optimum, we elucidate a transition, from a regime where the phenotypic gap of the adapting population from the optimum attains a stationary mean value to one where it increases indefinitely. Through a special case of the problem, we provide an alternative description of this transition in terms of a force that drives the adaptive process and a corresponding potential that switches from being confining to non-confining at the critical speed. Further analysis of this case suggests that adaptation is rather successfully carried out, until the population becomes limited by the maximum rate at which it can adapt. Remarkably, despite the simplicity of this special case, its predictions align well with observations from the original, more complex model [1].

[1] Sakshi Pahujani, Yuna Zhang, Markus G. Stetter, Joachim Krug, Adaptive Dynamics of Quantitative Traits in a Steadily Changing Environment, bioRxiv 2025.09.28.679017

Keywords: Evolution; Adaptation; Fitness Landscapes; Stochastic process; Adaptive walk