TWiEVO 79: When the immune system is away, SARS-CoV-2 will play
Nels and Vincent discuss an analysis of the drivers of evolution of SARS-CoV-2 during chronic infections, indicating that a tradeoff exists between antibody evasion and fitness.
fitness
Good viruses visiting bad neighborhoods
What would happen to an RNA virus if its genome were placed in a bad neighborhood? The answer is that fitness plummets. RNA virus populations are not composed of a single defined nucleic acid sequence, but are dynamic distributions of many nonidentical but related members. In the past I have referred to these populations as quasispecies but …
Describing a viral quasispecies
Virus populations do not consist of a single member with a defined nucleic acid sequence, but are dynamic distributions of nonidentical but related members called a quasispecies (illustrated at left). While next-generation sequencing methods have the capability of describing a quasispecies, the errors associated with this technology have limited progress in our understanding of the genetic …
Increased fidelity reduces viral fitness
We have spent over a week discussing the effects of polymerase error rates on viruses. RNA viruses have the highest error rates in nature, a property that is believed to benefit the viral population. For example, selective pressure from the immune system or antiviral drugs may lead to changes that are beneficial for the population. …