Question

What is a quasispecies, and what are some ways that it can contribute to pathogenesis of a virus such as Poliovirus?

Answer 1

A group of mutant viruses that develops as a virus replicates within a host. The viruses grouped in a quasispecies are related by a similar mutation.

A quasispecies is a well-defined distribution of mutants that is generated by a mutation-selection process. Selection does not act on a single mutant but on the quasispecies as a whole. Experimental systems have been designed to study quasispecies evolution under laboratory conditions. More recently, virus populations have been called quasispecies to indicate their extensive genetic heterogeneity. The most prominent examples are probably the human immunodeficiency viruses HIV-1 and HIV-2.