A Hamilton-Jacobi method to describe the evolutionary equilibria in heterogeneous environments and with non-vanishing effects of mutations

TL;DR

This paper introduces a Hamilton-Jacobi approach to analyze evolutionary equilibria in populations with heterogeneity and non-zero mutation effects, extending previous models by capturing more complex mutation dynamics.

Contribution

It generalizes Hamilton-Jacobi methods to include non-vanishing mutation effects, bridging adaptive dynamics and quantitative genetics.

Findings

Identifies dominant solution terms for small but non-zero mutations.

Provides a uniqueness property linked to weak KAM theory.

Extends beyond Gaussian approximations in evolutionary models.

Abstract

In this note, we characterize the solution of a system of elliptic integro-differential equations describing a phe-notypically structured population subject to mutation, selection and migration. Generalizing an approach based on Hamilton-Jacobi equations, we identify the dominant terms of the solution when the mutation term is small (but nonzero). This method was initially used, for different problems from evolutionary biology, to identify the asymptotic solutions, while the mutations vanish, as a sum of Dirac masses. A key point is a uniqueness property related to the weak KAM theory. This method allows to go further than the Gaussian approximation commonly used by biologists and is an attempt to fill the gap between the theories of adaptive dynamics and quantitative genetics.