Post by Nadica (She/Her) on Jun 17, 2024 3:06:52 GMT
The Two Faces of Mutation: Extinction and Adaptation in RNA Viruses - Published January 18, 2008
Not covid specific, but interesting nonetheless.
Highlight:
On the one hand, the high mutation rates in RNA viruses can lead to the accumulation of deleterious mutations, causing fitness declines and potentially driving viral extinction through Muller's ratchet in small populations. Experiments have shown significant fitness losses in viruses like vesicular stomatitis virus (VSV) and foot-and-mouth disease virus due to this process. On the other hand, the high genetic variability generated by rapid mutation enables rapid adaptation in RNA viruses.Beneficial mutations can arise and spread, allowing viruses to quickly adapt to new hosts or overcome antiviral drugs. Experiments demonstrate the ability of VSV to adapt to novel cell types and develop resistance to interferon. The review also discusses factors that influence the rate of adaptation, such as population size and clonal interference. Larger population sizes allow stronger competition between variants, leading to fixation of only the best mutations and slowing the overall rate of adaptation. The distribution and effects of beneficial mutations also impact the pace of adaptation.
In summary, the high mutation rates in RNA viruses are a double-edged sword - they can drive extinction through accumulation of deleterious mutations but also provide the genetic variation necessary for rapid adaptation to new environments and challenges.
My Commentary: With covid's novility and being widespread, we see both edges of this blade often as multiple mutations create long-lasting lineages, especially in those cryptic strains developed in long-term infections. Covid being so widespread means we cannot simply hope it mutates itself to extinction, as successful strains are spread easily without nonpharmaceutical intervention.
Abstract
From a population standpoint, two main features characterize the replication of RNA viruses and viruses that use RNA as a replicative intermediate: high genetic variability, and enormous fluctuations in population size. Their genetic variability mainly reflects a lack of the proof-reading and post-replicative error correction mechanisms that operate during cellular DNA replication, but recombination and segment exchange can also play an important role. Viral population size can change tremendously as a consequence of transmission between hosts or between different tissues within an infected host. A new infection can be initiated with very few particles that subsequently expand many trillion-fold. Repeated bottleneck events can lead to drastic fitness losses or even to viral extinction, whereas continuously large population sizes result in fitness gains and adaptation. Here we review experimental evidence for the effects of mutation, selection, and genetic drift on the adaptation and extinction of RNA viruses.
Not covid specific, but interesting nonetheless.
Highlight:
On the one hand, the high mutation rates in RNA viruses can lead to the accumulation of deleterious mutations, causing fitness declines and potentially driving viral extinction through Muller's ratchet in small populations. Experiments have shown significant fitness losses in viruses like vesicular stomatitis virus (VSV) and foot-and-mouth disease virus due to this process. On the other hand, the high genetic variability generated by rapid mutation enables rapid adaptation in RNA viruses.Beneficial mutations can arise and spread, allowing viruses to quickly adapt to new hosts or overcome antiviral drugs. Experiments demonstrate the ability of VSV to adapt to novel cell types and develop resistance to interferon. The review also discusses factors that influence the rate of adaptation, such as population size and clonal interference. Larger population sizes allow stronger competition between variants, leading to fixation of only the best mutations and slowing the overall rate of adaptation. The distribution and effects of beneficial mutations also impact the pace of adaptation.
In summary, the high mutation rates in RNA viruses are a double-edged sword - they can drive extinction through accumulation of deleterious mutations but also provide the genetic variation necessary for rapid adaptation to new environments and challenges.
My Commentary: With covid's novility and being widespread, we see both edges of this blade often as multiple mutations create long-lasting lineages, especially in those cryptic strains developed in long-term infections. Covid being so widespread means we cannot simply hope it mutates itself to extinction, as successful strains are spread easily without nonpharmaceutical intervention.
Abstract
From a population standpoint, two main features characterize the replication of RNA viruses and viruses that use RNA as a replicative intermediate: high genetic variability, and enormous fluctuations in population size. Their genetic variability mainly reflects a lack of the proof-reading and post-replicative error correction mechanisms that operate during cellular DNA replication, but recombination and segment exchange can also play an important role. Viral population size can change tremendously as a consequence of transmission between hosts or between different tissues within an infected host. A new infection can be initiated with very few particles that subsequently expand many trillion-fold. Repeated bottleneck events can lead to drastic fitness losses or even to viral extinction, whereas continuously large population sizes result in fitness gains and adaptation. Here we review experimental evidence for the effects of mutation, selection, and genetic drift on the adaptation and extinction of RNA viruses.