Why Are Viral Genomes So Fragile? The Bottleneck Hypothesis

Authors: Merleau NSC, Pénisson S, Gerrish PJ, et al.

Published in: PLoS Computational Biology (2021)

Citations: 12

Abstract:
Viral RNA genomes are remarkably short and fragile — prone to lethal mutation accumulation — compared to DNA genomes of similar complexity. This paper proposes the bottleneck hypothesis: repeated population bottlenecks during host-to-host transmission drastically reduce effective population size, relaxing purifying selection. Using mathematical models of mutation-selection balance under variable bottleneck severity, the authors show that bottleneck size alone explains the observed fragility gradient across viruses without invoking error-prone replication as the primary cause.