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Published on: March 19, 2015
Avian influenza virus exhibits rapid evolutionary dynamics
1Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, PA, USA.
Molecular Biology and Evolution
|September 2, 2006
Summary
Avian influenza viruses (AIV) evolve rapidly, contrary to previous beliefs of stasis. This rapid evolution, observed across wild and domestic species, suggests a high mutation rate and fast replication cycle for influenza A virus.
Area of Science:
- Virology
- Evolutionary Biology
- Genomics
Background:
- Influenza A viruses (IAV) in wild aquatic birds, the natural reservoir, were hypothesized to exhibit evolutionary stasis.
- This presumed low rate of evolutionary change was thought to be characteristic of these viruses.
Purpose of the Study:
- To test the hypothesis of evolutionary stasis in avian influenza viruses (AIV).
- To estimate nucleotide substitution rates and evolutionary dynamics across diverse AIV lineages.
Main Methods:
- Estimation of nucleotide substitution rates in a diverse array of avian influenza viruses.
- Analysis allowing for rate variation among different viral lineages.
Main Results:
- Observed extremely high substitution rates (>10^-3 substitutions per site per year) in AIV.
- Found minimal differences in evolutionary rates between wild and domestic host species and viral subtypes.
- Rates were comparable to those observed in mammalian influenza A viruses.
Conclusions:
- Influenza A virus demonstrates rapid evolutionary dynamics across its host range.
- This rapid evolution is consistent with a high background mutation rate and rapid replication.
- The common ancestors of AIV hemagglutinin and neuraminidase sequences emerged within the last 3,000 years, with most diversity arising in the last century, suggesting continuous selective turnover.
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