- Viral evolution
Viral evolution is a subfield of
evolutionary biology that is specifically concerned with theevolution ofvirus es. Manyvirus es, in particularRNA virus es, have short generation times and relatively high mutation rates (on the order of one point mutation or more per genome per round of replication for RNA viruses). This elevated mutation rate, when combined withnatural selection , allows viruses to quickly adapt to changes in their host environment.Viral evolution is an important aspect of the
epidemiology of viral diseases such asinfluenza ,HIV , andhepatitis . It also causes problems in the development of successfulvaccine s andantiviral drugs, as resistant mutations often appear within weeks or months after the beginning of the treatment.RNA viruses are also used as a model system to study evolution in the laboratory.
One of the main theoretical models to study viral evolution is the
quasispecies model , as theviral quasispecies .Inter-host and Intra-host evolution
In evolutionary virology and to an extent in the wider field of
pathology , inter-host evolution is considered to represent the geological, i.e. visible or detectable,evolution of avirus while intra-host evolution represents the invisible evolution of a virus. Adaptive changes acquired by inter-host evolution are rarely lost once acquired. Changes acquired by intra-host evolution may be lost if the evolutionary landscape changes, for example: a population of viruses may become resistant to anantiviral drug while the host (patient) takes it, but rapidly revert towild-type if treatment ceases.Changes may include
point mutations or epistatic mutations, as well asgenome rearrangements togenes and otherfunctional gene sequences such asgene acquisition ,gene creation and gene deletion as well as recombination and translocation events.ee also
*
Viral classification
*RNA virus
*DNA virus
*Viral quasispecies Further reading
* E. Domingo and C.K. Biebricher and M. Eigen and J.J. Holland (2002). "Quasispecies and RNA Virus Evolution: Principles and Consequences." Landes Bioscience.
* S.F. Elena andR. E. Lenski (2003). Evolution experiments with microorganisms: the dynamics and genetic bases of adaptation. "Nat. Rev. Genet." 4:457-469.
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