Article,

The tempo of linked selection: Rapid emergence of a heterogeneous genomic landscape during a radiation of monkeyflowers

, , , , and .
bioRxiv, (2018)
DOI: 10.1101/342352

Abstract

What are the processes that shape patterns of genome-wide variation between emerging species? This question is central to our understanding of the origins of biodiversity and the fundamental principles governing molecular evolution. It is becoming clear that indirect selection on linked neutral variation (hereafter, linked selection) plays a pervasive role in shaping heterogeneous patterns of genome-wide diversity and differentiation within and between species, but we do not know how these signatures of linked selection evolve over time. To fill this critical knowledge gap, we construct the first chromosome-level genome assembly for the bush monkeyflower, and use it to show that linked selection has been a primary architect of heterogeneous patterns of lineage sorting, differentiation, and nucleotide diversity across a recent radiation. By taking advantage of the range of divergence times between the different pairs of monkeyflower taxa, we also show how the signatures of linked selection evolve as populations diverge: linked selection occurring within lineages acts to conserve an ancestral pattern of diversity after a population split, while its joint action in separate lineages causes a common differentiation landscape to rapidly emerge between them. Together, our study demonstrates how pervasive linked selection shapes patterns of genome-wide variation within and between taxa, and provides critical insight into how its singiature evolves during the first 1.5 million years of divergence.

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