title: [Characterization of HA1 gene of influenza B virus circulated in 1990 through 2000 in China].
abstract: OBJECTIVE
  To characterize HA1 gene of influenza B virus circulated in 1990 through 2000 in China.
  
  
  METHODS
  Viral RNA was extracted and transcribed into cDNA by reverse transcriptase and amplified by PCR. The product of PCR was purified and sequenced by ABI377. The sequence data were analyzed with epidemic records.
  
  
  RESULTS
  1. Two major lineages of influenza B virus always circulated during the period of 1990-2000 in China; the Yamagata lineage was the main lineage, but in 1994 and 1997 the Victoria lineage was more active. 2. During 1992-2000 the Yamagata lineage evolved into two minor groups whose distance in HAI amino acid sequences was about 6%. 3. Large and non-reverse mutators led the development of influenza B epidemics in 1990-2000 in China. 4. Except for a few strains, there was little difference among the influenza B viruses of the same major lineages circulated in the same year in China.
  
  
  CONCLUSIONS
  Two major lineages of influenza B virus always circulated during the period from 1990-2000 in China,and the Yamagata lineage diverged into two minor groups in recent years. Exchanges of the lineages and the appearance of large non-reverse mutators possibly had important epidemic significance.
authors.affiliation: Chinese National Influenza Center, Institute of Virology, Chinese Academy of Preventive Medicine, Beijing 100052, China.
authors.forename: Jiming
authors.initials: J
authors.lastname: Chen
authors.forename: Yuanji
authors.initials: Y
authors.lastname: Guo
authors.forename: Junfeng
authors.initials: J
authors.lastname: Guo
authors.forename: Jie
authors.initials: J
authors.lastname: Dong
mesh_terms: D002681:China / Q000453:epidemiology; D005814:Genes, Viral / Q000235:genetics*; D009981:Influenza B virus / Q000145:classification / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D012367:RNA, Viral