EVERYDAY SCIENCE

Detailed explanation-1: -RNA viruses like poliovirus likely have higher mutation rates than what would be optimal for the organism because higher mutation rates are, in part, a byproduct of selection for faster genomic replication.

Detailed explanation-2: -RNA viruses are characterized by high mutation rates compared with most DNA systems (1), due mainly to the lack of exonuclease proofreading activity displayed by their RNA polymerases (2).

Detailed explanation-3: -RNA viruses, however, have higher mutation rates that range between 10−6 and 10−4 s/n/c (Fig.

Detailed explanation-4: -Measurements during infections and with purified viral polymerases indicate that mutation rates for RNA viruses are in the range of 10−3 to 10−6 copying errors per nucleotide incorporated into the nascent RNA product.

Detailed explanation-5: -RNA viruses exploit all known mechanisms of genetic variation to ensure their survival. Distinctive features of RNA virus replication include high mutation rates, high yields, and short replication times. As a consequence, RNA viruses replicate as complex and dynamic mutant swarms, called viral quasispecies.