title: Prevalent HBV genotypes and subtypes in a South Indian population.
abstract: BACKGROUND
  Genotypes or genetic subtypes describe genetically related strains and have been described for viruses belonging to several different families. The eight major genotypes of hepatitis B virus (HBV) have distinct geographic distribution. Recent studies suggest possible pathogenic and therapeutic differences among HBV genotypes.
  
  
  OBJECTIVE
  To evaluate the HBV genotypes of 85 samples by RFLP analysis and sequence the desired region to look for variations and identify the subtypes of the surface region.
  
  
  METHODS
  We studied 85 patients with HBV in order to identify the most prevalent genotype and subtype. Patients with HBV-related liver disease attending the Department of Gastroenterology at Owaisi Hospital and Research Centre were studied.
  
  
  CONCLUSIONS
  Genotype D1 was most prevalent. Genotyping was carried out by RFLP analysis and confirmed by sequencing. Nucleotide sequences showed significant homology (96-97%) with the other genotypes that have been reported. Subtype ayw was the most prevalent subtype within the surface region. Construction of a phylogenetic tree incorporating these isolates and other published HBV sequences showed that the isolates are derived from the same evolutionary tree. The study adds to our understanding of the genetic diversity of HBV and the geographical distribution of its subtypes, and will be useful for reconstructing the evolutionary history of HBV.
authors.affiliation: Centre for Liver Research and Diagnostics, Deccan College of Medical Sciences and Allied Hospitals, Kanchanbagh, Hyderabad 500 058, Andhra Pradesh, India.
authors.forename: Rekha
authors.initials: R
authors.lastname: Thippavazzula
authors.forename: Chandrakala
authors.initials: C
authors.lastname: Mogili
authors.forename: Madhavi
authors.initials: M
authors.lastname: Chandra
authors.forename: Mohammed Nanne
authors.initials: MN
authors.lastname: Khaja
authors.forename: Mohammed Aejaz
authors.initials: MA
authors.lastname: Habeeb
authors.forename: Chitoor Mohammed
authors.initials: CM
authors.lastname: Habibullah
mesh_terms: D000328:Adult; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004279:DNA, Viral / Q000235:genetics; D019143:Evolution, Molecular; D005260:Female; D005838:Genotype; D005843:Geography; D006509:Hepatitis B / Q000821:virology*; D006515:Hepatitis B virus / Q000145:classification* / Q000235:genetics*; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004279:DNA, Viral