Evolutionary characterization of the pandemic H1N1/2009 influenza virus in humans based on non-structural genes

PLoS One. 2013;8(2):e56201. doi: 10.1371/journal.pone.0056201. Epub 2013 Feb 13.


The 2009 influenza pandemic had a tremendous social and economic impact. To study the genetic diversity and evolution of the 2009 H1N1 virus, a mutation network for the non-structural (NS) gene of the virus was constructed. Strains of the 2009 H1N1 pandemic influenza A virus could be divided into two categories based on the V123I mutation in the NS1 gene: G1 (characterized as 123 Val) and G2 (characterized as 123 Ile). Sequence homology analysis indicated that one type of NS sequence, primarily isolated from Mexico, was likely the original type in this pandemic. The two genotypes of the virus presented distinctive clustering features in their geographic distributions. These results provide additional insight into the genetics and evolution of human pandemic influenza H1N1.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Evolution, Molecular*
  • Gene Frequency
  • Gene Regulatory Networks
  • Genetic Variation
  • Genotype
  • Geography
  • Humans
  • Influenza A Virus, H1N1 Subtype / classification
  • Influenza A Virus, H1N1 Subtype / genetics*
  • Influenza, Human / epidemiology
  • Influenza, Human / virology
  • Models, Genetic
  • Mutation*
  • Pandemics
  • Phylogeny
  • Selection, Genetic
  • Species Specificity
  • Viral Nonstructural Proteins / classification
  • Viral Nonstructural Proteins / genetics*


  • INS1 protein, influenza virus
  • NS2 protein, influenza virus A
  • Viral Nonstructural Proteins

Grants and funding

This study was supported by the knowledge innovation program of the Chinese academy of sciences (KSCX2-EW-J-2), the National Science and Technology Ministry (2009BAI83B01), National Natural Sciences Foundation of China (31101806) and USDA/APHIS/WS-IOZ CAS joint project (0760621234). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.