title: [Application of gene sequence cluster in research for H3 antigenic evolution of influenza A virus].
abstract: OBJECTIVE
  Gene sequence data were clustered to explore evolution lineages of H3 antigen of influenza A virus.
  
  
  METHODS
  All data of H3 RNA sequence in NCBI Genbank and Influenza sequence database were downloaded and aligned in ClustalX while two step cluster method were applied to explore the data.
  
  
  RESULTS
  All sequences were aggregated into ten clusters, while seven of them mainly were human virus. Human virus and avian/other mammal virus were separated into different clusters distinctively, but coexisted into same clusters with swine virus. Time and host distribution were very distinctive in these clusters, but no geographic distribution features were found.
  
  
  CONCLUSIONS
  With the interaction of human immunity system, H3 antigen mutated significantly every 5 - 7 years, and the speed of mutation had accelerated with the application of influenza vaccines in recent years. Mean while, human and swine influenza virus were not separated distinctly between clusters indicating that they had short inheritance distance. Result showed again that swine served as the mixer for antigenic recombination of different influenza virus.
authors.affiliation: Department of Health Statistic, School of Public Health, Fudan University, Shanghai 200032, China.
authors.forename: Wen-Tong
authors.initials: WT
authors.lastname: Zhang
authors.forename: Qing-Wu
authors.initials: QW
authors.lastname: Jiang
authors.forename: Lu-Fang
authors.initials: LF
authors.lastname: Jiang
authors.forename: Li-Wen
authors.initials: LW
authors.lastname: Ju
mesh_terms: D000940:Antigenic Variation / Q000235:genetics; D000956:Antigens, Viral / Q000235:genetics*; D016000:Cluster Analysis; D019143:Evolution, Molecular; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics*; D006389:Hemagglutinins, Viral / Q000235:genetics / Q000276:immunology; D006801:Humans; D009980:Influenza A virus / Q000235:genetics* / Q000276:immunology*; D009154:Mutation; D017422:Sequence Analysis, DNA; D014759:Viral Envelope Proteins / Q000235:genetics
chemical_list: D000956:Antigens, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral; D014759:Viral Envelope Proteins