title: Distribution and epidemiologic trends of HBV genotypes and subtypes in 14 countries neighboring china.
abstract: BACKGROUND
  The number of cases of HBV infection reported by the WHO for each district and country is positively correlated with the number of HBV sequences in the database isolated from the corresponding district and country.
  
  
  OBJECTIVE
  This study determined distribution characteristics of HBV genotypes and subtypes in 14 countries neighboring China. The progress made in genomic research involving HBV was also reviewed.
  
  
  METHODS
  Nine hundred fifty-one complete genome sequences of HBV from 14 countries neighboring China were selected from NCBI. The sequence-related information was analyzed and recorded. One hundred seventy-two sequences of HBV genotype B were screened for alignment using DNA star and MEGA 5.1.
  
  
  RESULTS
  Dominant HBV genotypes in the countries neighboring China were genotypes B, C and D and dominant subtypes were adw2 and adrq+. The association between genotype and serotype of HBV in these countries was shown to differ from previous research results. As shown by sequence alignment, the sequence divergence between five subgenotypes (B3, B5, B7, B8 and B9) was below 4%. The B subgenotypes shared six common specific amino acid sites in the S region.
  
  
  CONCLUSIONS
  The B3, B5, B7, B8 and B9 subgenotypes can be clustered into quasi-sub-genotype B3 and the open reading frame of HBV has a start codon preference; however, whether a mutation in the start codon in the pre-S2 region has an impact on survival and replication of HBV remains to be determined.
authors.affiliation: Kunming Medical College, Kunming, Yunnan, China ; Institute of Basic and Clinical Medicine, Provincial Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Affiliated Hospital of Kunming Science and Technology University, Kunming, Yunnan Province, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Qian
authors.affiliation: Clinical Laboratory, the First People's Hospital of Yunnan Province, Kunming, Yunnan Province, China.
authors.forename: Wang
authors.initials: W
authors.lastname: Jianqiong
authors.affiliation: Institute of Basic and Clinical Medicine, Provincial Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Affiliated Hospital of Kunming Science and Technology University, Kunming, Yunnan Province, China ; Kunming Science and Technology University, Kunming, Yunnan, China.
authors.forename: Li
authors.initials: L
authors.lastname: Hongmei
authors.affiliation: Institute of Basic and Clinical Medicine, Provincial Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Affiliated Hospital of Kunming Science and Technology University, Kunming, Yunnan Province, China.
authors.forename: Zeng
authors.initials: Z
authors.lastname: Rong
authors.affiliation: Institute of Basic and Clinical Medicine, Provincial Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Affiliated Hospital of Kunming Science and Technology University, Kunming, Yunnan Province, China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Institute of Basic and Clinical Medicine, Provincial Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Affiliated Hospital of Kunming Science and Technology University, Kunming, Yunnan Province, China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Jinping
authors.affiliation: Institute of Basic and Clinical Medicine, Provincial Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Affiliated Hospital of Kunming Science and Technology University, Kunming, Yunnan Province, China.
authors.forename: Shen
authors.initials: S
authors.lastname: Tao
keywords: Epidemiology; Genomics; Serotype