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 a virus 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 an antiviral drug while the host (patient) takes it, but rapidly revert to wild-type if treatment ceases. Viral Infection tend to have a short generation time and a relatively high mutation rate. Changes may include point mutations or epistatic mutations, as well as genome rearrangements to genes and other functional gene sequences such as gene acquisition, gene creation and gene deletion as well as recombination and translocation events.
Read more about this topic: Viral Evolution
Famous quotes containing the word evolution:
“By contrast with history, evolution is an unconscious process. Another, and perhaps a better way of putting it would be to say that evolution is a natural process, history a human one.... Insofar as we treat man as a part of nature—for instance in a biological survey of evolution—we are precisely not treating him as a historical being. As a historically developing being, he is set over against nature, both as a knower and as a doer.”
—Owen Barfield (b. 1898)