Selection, recombination, and the ancestral initiation graph

TL;DR

This paper introduces the ancestral initiation graph, a new method for analyzing selection and recombination in genetic models, providing clearer insights into linkage disequilibrium dynamics and the influence of the selected site position.

Contribution

The paper presents the ancestral initiation graph, an accessible alternative to the ancestral selection-recombination graph, based on discretising the selection-recombination equation.

Findings

Explains the dynamics of linkage disequilibrium between neutral loci.

Clarifies the dependence of linkage disequilibrium on the position of the selected site.

Provides a systematic explanation for long-standing observations in genetic linkage studies.

Abstract

Recently, the selection-recombination equation with a single selected site and an arbitrary number of neutral sites was solved by means of the ancestral selection-recombination graph. Here, we introduce a more accessible approach, namely the ancestral initiation graph. The construction is based on a discretisation of the selection-recombination equation. We apply our method to systematically explain a long-standing observation concerning the dynamics of linkage disequilibrium between two neutral loci hitchhiking along with a selected one. In particular, this clarifies the nontrivial dependence on the position of the selected site.