Which one of the following statements explains higher mutation rate and faster evolution found in RNA virus?

RNA viruses exhibit significantly higher mutation rates and faster evolution compared to DNA viruses primarily because RNA is relatively unstable and the replication process is highly error-prone [4]. Unlike DNA replication, which utilizes DNA-dependent DNA polymerases with sophisticated proofreading capabilities, most RNA viruses rely on RNA-dependent RNA polymerase (RdRp) [4]. These enzymes generally lack proofreading exonuclease activity, leading to spontaneous mutation rates up to a million times higher than their hosts [2]. This lack of a repair mechanism results in approximately 10⁻⁴ to 10⁻⁶ errors per nucleotide site per round of replication. While high mutation rates can lead to defective particles, they provide a clear evolutionary advantage by allowing viruses to generate antigenic variants that escape host immune responses and adapt rapidly to new environments [4]. Consequently, the chemical instability of the RNA genome and the low fidelity of its replication machinery drive this rapid evolution [1].

Sources

1. [1] https://pmc.ncbi.nlm.nih.gov/articles/PMC5075021/
2. [4] https://pmc.ncbi.nlm.nih.gov/articles/PMC5850383/
3. [2] https://pmc.ncbi.nlm.nih.gov/articles/PMC6107253/