Ancestry in adapting, spatially-extended populations

TL;DR

This paper investigates how multiple unlinked selective sweeps in spatially-extended populations influence the overall patterns of ancestry and neutral genetic diversity across the entire genome, unlike in panmictic populations.

Contribution

It demonstrates that in spatially-structured populations, even low rates of sweeps can significantly skew ancestry patterns across the genome.

Findings

Unlinked sweeps impact genome-wide ancestry in spatial populations

Low sweep rates can prevent neutral mutations from fixing outside central regions

Spatial ancestry patterns are more affected by sweeps than in panmictic populations

Abstract

Selective sweeps affect neutral genetic diversity through hitchhiking. While this effect is limited to the local genomic region of the sweep in panmictic populations, we find that in spatially-extended populations the combined effects of many unlinked sweeps can affect patterns of ancestry (and therefore neutral genetic diversity) across the whole genome. Even low rates of sweeps can be enough to skew the spatial locations of ancestors such that neutral mutations that occur in an individual living outside a small region in the center of the range have virtually no chance of fixing in the population.