TABLE I.
Biological Relevance of Quasispecies Dynamics for RNA Virusesa
| Relevant parameters |
|---|
| 1.Average number of mutations per genome found in a viral population: typically it ranges from 1 to 100 |
| 2.Virus population size: very variable but can reach 109 to 1012 in some infections in vivo |
| 3.Genome length: 3 to 33 kb, with compact genetic information |
| 4.Mutations needed for a phenotypic change: one or few mutations, as documented amply in the text for changes in receptor recognition specificity |
| Examples of phenotypic changes in RNA viruses dependent on one or few mutations |
| 1.Antigenic variation (antibody-, CTL-escape) |
| 2.Virulence |
| 3.Altered pattern of gene expression |
| 4.Resistance to antiviral inhibitors |
| 5.Cell tropism and host range (the topic of this review) |
a
Based on many published studies reviewed in Domingo 1985, Domingo 1999, Domingo 2001, Crandall 1999, Flint 2000, DeFilippis 2001.