Speaker
Description
Ageing's sensitivity to natural selection has long been discussed because of its apparent negative effect on an individual's fitness. Thanks to the recently described (Smurf) 2-phase model of ageing (data of Michael Rera) we propose a fresh angle for modeling the evolution of ageing. Indeed, by coupling a dramatic loss of fertility with a high-risk of impending death—amongst other multiple so-called hallmarks of ageing—the Smurf phenotype allowed us to consider ageing as a couple of sharp transitions. The birth–death model we describe here is a simple life-history trait model where each asexual and haploid individual is described by its fertility period $x_b$ and survival period $x_d$. We show that $x_b$ and $x_d$ converge during evolution to configurations $x_b − x_d \approx$ constant in finite time. To do so, we built an individual-based stochastic model which describes the age and trait distribution dynamics of such a finite population.Then we rigorously derive the adaptive dynamics models, which describe the trait dynamics at the evolutionary time-scale. We extend the Trait Substitution Sequence with age structure and study the limiting behaviour of this jump process when mutations are small. We show that the limiting behaviour is described by a differential equation for $(x_b,x_d)$. It's a joint work with Michael Réra and Tristan Roget.
