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Virus Evolution

  1. Esteban Domingo,
  2. Celia Perales

Published Online: 15 APR 2014

DOI: 10.1002/9780470015902.a0000436.pub3

eLS

eLS

How to Cite

Domingo, E. and Perales, C. 2014. Virus Evolution. eLS. .

Author Information

  1. Centro de Biología Molecular ‘Severo Ochoa’ (CSIC–UAM), Madrid, Spain

Publication History

  1. Published Online: 15 APR 2014

Abstract

Viruses are transmissible deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) genetic elements that require a cell for multiplication. Viruses are extremely diverse and ubiquitous in nature. They evolve in continuous interaction with their host cells and organisms, following the general Darwinian principles: genetic variation, competition among variant forms and selection of the most fit variants in a given environment. Viruses probably had an ancient origin and have survived as agents of gene transfer and promoters of cell variation. Evolution of RNA viruses and some DNA viruses can be extremely rapid, fuelled by limited template-copying fidelity of the replicating polymerases. They form extremely complex mutant clouds termed viral quasispecies, which can acquire features not explainable from the individuals that compose the ensemble. Quasispecies dynamics not only represent a problem for disease prevention and control, but it has inspired new strategies to combat viral disease. One of them is lethal mutagenesis or viral extinction driven by an excess of mutations, often produced by mutagenic nucleotide analogues. New antiviral designs based on lethal mutagenesis are currently under investigation.

Key Concepts:

  • Virions are the virus particles produced on completion of the intracellular replication cycle.

  • Interhost transmission of virions can give rise to disease outbreaks, epidemics or pandemics.

  • Metagenomic studies using deep sequencing methods have unveiled great diversity of viruses in many natural habitats.

  • The ensemble of viruses in our biosphere is termed the ‘virosphere’.

  • Evidence from comparative genomics suggests a long coevolution of cells and viruses on Earth.

  • Recombination and horizontal gene transfers between viral and cellular genes have been abundant during evolution of life.

  • Some proteins that play physiological functions in cells can be recruited as part of the innate immunity against viruses.

  • Population bottlenecks may alter viral fitness and influence evolutionary outcomes.

  • The adaptive potential of viral quasispecies has encouraged research in new strategies for viral disease prevention and control.

Keywords:

  • genome replication;
  • genetic variation;
  • coevolution;
  • quasispecies;
  • mutation;
  • recombination