Lines of descent in a Moran model with frequency-dependent selection and mutation

TL;DR

This paper investigates the ancestral structures of a two-type Moran model with mutation and frequency-dependent selection, developing new graphical tools and dualities to understand type distributions under various regimes.

Contribution

It introduces killed and pruned lookdown ancestral selection graphs for frequency-dependent selection, extending analysis to diffusion limits and diverse population sizes.

Findings

Same type-frequency process under different selection schemes

Development of killed and pruned lookdown ASG methods

Application to finite and large populations with various selection intensities

Abstract

We study ancestral structures for the two-type Moran model with mutation and frequency-dependent selection under the nonlinear dominance or fittest-type-wins scheme. Under appropriate conditions, both lead, in distribution, to the same type-frequency process. Reasoning through the mutations on the ancestral selection graph (ASG), we develop the corresponding killed and pruned lookdown ASG and use them to determine the present and ancestral type distributions. To this end, we establish factorial moment dualities to the Moran model and a relative. We extend the results to the diffusion limit and present applications for finite population size as well as moderate and weak selection.