Genetic bottlenecks in intraspecies virus transmission

Abstract

Ultimately, viral evolution is a consequence of mutations that arise within and spread between infected hosts. The transmission bottleneck determines how much of the viral diversity generated in one host passes to another during transmission. It therefore plays a vital role in linking within-host processes to larger evolutionary trends. Although many studies suggest that transmission severely restricts the amount of genetic diversity that passes between individuals, there are important exceptions to this rule. In many cases, the factors that determine the size of the transmission bottleneck are only beginning to be understood. Here, we review how transmission bottlenecks are measured, how they arise, and their consequences for viral evolution.

Prisoners of war — host adaptation and its constraints on virus evolution

“…bottlenecks that reduce effective population sizes that occur as the virus transmits between hosts 15 . Sequence change may be augmented by adaptive changes.…”

Virus–Host Coevolution with a Focus on Animal and Human DNA Viruses

“…As a substantial evolutionary effect on the population dynamics of viruses, genetic bottleneck (reduction of effective population size due to environmental events, for instance new habitat colonisation) affects the virus-host coevolution: it decreases both the genetic variation and the fitness of the virus, and furthermore it is responsible for the founder effect (Novella et al 1995). Changes of genotype frequencies by stochastic population size reduction are referred to as genetic drift (Bergstrom et al 1999;Dennehy et al 2006;Elena et al 2001;McCrone and Lauring 2018;Zwart and Elena 2015). Furthermore, it is important to stress that the phenomenon of genetic bottleneck is interpretable from both virus and host perspective (Voskarides et al 2018).…”

Evolutionary Virology at 40

“…Indeed, while there is some evidence from experimental systems that multiple viral variants can be transmitted between cells that could lead to cooperation-like interactions (Combe et al 2015), experimental populations may often fail to mirror the natural situation. Most pointedly, it is uncertain how cooperation could be selectively maintained in the face of the severe population bottlenecks, particularly those that commonly occur when viruses transmit to new hosts (Geoghegan et al 2016b;McCrone and Lauring 2018;. Transmission bottlenecks inevitably impinge on evolutionary processes that require groups of viruses to interact (Aaskov et al 2006) and make it difficult to translate withinhost evolution to that over epidemiological timescales (Figure 1).…”