Send to

Choose Destination
See comment in PubMed Commons below
Trends Ecol Evol. 1992 Apr;7(4):118-21. doi: 10.1016/0169-5347(92)90145-2.

What is a quasispecies?

Author information

Martin Nowak is at the Dept of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.


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. The quasispecies nature of HIV has formed the basis of a model that provides a mechanism for the pathogenesis of acquired immunodeficiency syndrome (AIDS) in humans. This article focuses on the nature of the quasispecies concept and its implications for evolutionary biology and virology.

PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center