Long intervals of stasis punctuated by bursts of positive selection in the seasonal evolution of influenza A virus
2006

Influenza A Virus Evolution: Stasis and Selection

Sample size: 994 publication 10 minutes Evidence: moderate

Author Information

Author(s): Wolf Yuri I, Viboud Cecile, Holmes Edward C, Koonin Eugene V, Lipman David J

Primary Institution: National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA

Hypothesis

The evolution of influenza A virus is characterized by long periods of stasis interrupted by bursts of positive selection.

Conclusion

Influenza A virus evolution consists of extended intervals of stasis, punctuated by shorter intervals of rapid fitness increase driven by positive selection.

Supporting Evidence

  • Phylogenetic analyses revealed long intervals of neutral evolution in H3N2 HA.
  • Positive selection was observed during rapid evolution intervals.
  • Stasis periods were characterized by an excess of synonymous substitutions.
  • Parallel amino acid replacements were detected in H3N2 HA.
  • Statistical tests indicated significant differences in mutation rates.

Takeaway

Influenza A virus changes slowly most of the time, but sometimes it changes quickly to escape the immune system.

Methodology

Phylogenetic analyses of HA sequences from 1995–2005 isolates of H3N2 and H1N1 subtypes.

Potential Biases

The dataset may not represent global diversity due to geographical bias.

Limitations

The sample is geographically limited to New York State and New Zealand.

Participant Demographics

Clinical isolates from New York State and New Zealand.

Statistical Information

P-Value

0.0017

Statistical Significance

p=0.0017

Digital Object Identifier (DOI)

10.1186/1745-6150-1-34

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