Which statement best describes the mutation rate of RNA viruses like influenza?

Which statement best describes the mutation rate of RNA viruses like influenza?

• A. RNA viruses have poorer replication fidelity leading to frequent mutations
• B. Mutation rate is identical across virus types
• C. DNA viruses mutate more frequently
• D. Mutation only arises during latency

Answer: (A)

RNA viruses have higher mutation rates because their RNA-dependent RNA polymerases generally lack proofreading. This means errors introduced during each replication cycle are not efficiently corrected, leading to frequent mutations and a diverse viral population. For influenza, this rapid generation of variants drives antigenic drift, helping the virus evade immunity and complicate vaccine design. In contrast, DNA viruses usually mutate more slowly because their polymerases have proofreading activity and repair mechanisms. Mutations occur during replication, not just during latency, so the idea that changes only arise in latent periods isn’t correct.

RNA viruses have higher mutation rates because their RNA-dependent RNA polymerases generally lack proofreading. This means errors introduced during each replication cycle are not efficiently corrected, leading to frequent mutations and a diverse viral population. For influenza, this rapid generation of variants drives antigenic drift, helping the virus evade immunity and complicate vaccine design. In contrast, DNA viruses usually mutate more slowly because their polymerases have proofreading activity and repair mechanisms. Mutations occur during replication, not just during latency, so the idea that changes only arise in latent periods isn’t correct.