Lines of descent under selection

TL;DR

This paper reviews recent advances in ancestral processes within mutation-selection models, focusing on the killed and pruned lookdown ancestral selection graphs to understand genetic ancestry and type distribution.

Contribution

It introduces and compares the killed and pruned lookdown ancestral selection graphs, providing new insights into ancestral type distributions in mutation-selection models.

Findings

Representation of individual types via ancestral graphs

Connection between ancestral graphs and stationary distributions

Application to error threshold phenomenon

Abstract

We review recent progress on ancestral processes related to mutation-selection models, both in the deterministic and the stochastic setting. We mainly rely on two concepts, namely, the killed ancestral selection graph and the pruned lookdown ancestral selection graph. The killed ancestral selection graph gives a representation of the type of a random individual from a stationary population, based upon the individual's potential ancestry back until the mutations that define the individual's type. The pruned lookdown ancestral selection graph allows one to trace the ancestry of individuals from a stationary distribution back into the distant past, thus leading to the stationary distribution of ancestral types. We illustrate the results by applying them to a prototype model for the error threshold phenomenon.