Viral Genome Evolution

What is the main reason why viruses evolve faster than cells?

What events can contribute to viral evolution by generating new viral strains?

What is the result of genome reassortment events in viral evolution?

What is the primary factor that allows viruses to evolve faster than cells?

What type of viral genome is more prone to reassortment events?

What is the outcome of the coinfection of a host cell by two different viral strains?

What is the role of random mutations in viral evolution?

Why are reassortment events important in viral evolution?

What is the main reason why RNA viruses tend to evolve faster than DNA viruses?

What is the term for genetic changes that limit infectivity, making them ideal for vaccine development?

What is the result of an advantageous mutation in a virus?

What is the term for the process by which a virus's genome changes over time due to random mutations?

What is an example of a virus that evolved enhanced infectivity traits, further complicating a pandemic?

What is the purpose of using attenuated viral strains in vaccine development?

Viral Evolution

Viruses evolve faster than cells due to their rapid replication and high numbers, allowing for more opportunities for natural selection to fine-tune transmission and infection strategies.
Reassortment events and random mutations contribute to viral evolution, especially in RNA viruses.

Reassortment Events and Random Mutations

Genome reassortment occurs when two different viral strains coinfect a single host cell, allowing for the mixing of viral genomes and generation of new viral strains.
Random mutations also cause viral genomes to change over time, with RNA viruses evolving faster than DNA viruses.
RNA polymerases lack proofreading capabilities, resulting in higher mutation frequencies (once per round of genome copying) compared to DNA polymerases (once per thousand rounds of genome copying).

Consequences of Mutation

Mutations can have neutral, beneficial, or negative effects depending on their location in the genome.
Genetic changes that limit infectivity are unfavorable and result in attenuated strains, which are ideal for vaccine development (e.g., oral polio vaccine).
Beneficial mutations can allow viruses to escape host immune system detection, broaden host range, expand tropism, or increase infectivity.

Examples of Viral Evolution

SARS-CoV-2 evolved enhanced infectivity traits, complicating the COVID-19 pandemic.
Influenza viruses are a classic model for studying the effects of spontaneous mutations and reassortment in viral evolution.

Explore how viral genomes change over time, factors contributing to rapid evolution, and the role of reassortment events and mutations in viral evolution.