Events Archive

Mittwoch, 22. Januar 2020, 14:15 Uhr, Robert-Mayer-Straße 10 in Raum 711 gr

14:00 Uhr: Vortrag von Dr. Charline Smadi, Universität Grenoble

Crossing a fitness valley as a metastable transition in a stochastic population model

We consider a stochastic model of population dynamics where each individual is characterised by a trait in {0,1,...,L} and has a natural reproduction rate, a logistic death rate due to age or competition, and a probability of mutation towards neighbouring traits at each reproduction event. We choose parameters such that the induced fitness landscape exhibits a valley: mutant individuals with negative fitness have to be created in order for the population to reach a trait with positive fitness. We focus on the limit of large population and rare mutations at several speeds. In particular, when the mutation rate is low enough, metastability occurs: the exit time of the valley is an  exponentially distributed random variable.

This is a joint work with Anton Bovier and Loren Coquille