title: Intra- and intergenotypic variations among human cytomegalovirus gB genotypes.
abstract: OBJECTIVE
  To study genotypic variations among human cytomegalovirus (HCMV) gB genotypes in clinical samples of Thai patients.
  
  
  METHODS
  gB genotyping of 31 HCMV-DNA-positive clinical samples were determined by PCR-RFLP, gene cloning and DNA sequencing methods.
  
  
  RESULTS
  Eight gB1, 7 gB2, 7 gB3, 6 gB untype (UT1 and UT2) and 3 mixed gB genotypes were first identified by PCR-RFLP. All 3 mixed gB genotype samples and 1 gB2 sample were cloned and confirmed gB genotype by PCR-RFLP. Altogether, 57 strains (27 unique types and 30 transformants) were further analyzed by DNA sequencing method. Discordant results between PCR-RFLP and DNA sequencing methods were demonstrated in 5 samples and 1 clone. The gB UT1 and UT2 were all classified as gB1 except 1 sample of UT1 (9D), suggesting a new variant. Each genotype had a similarity of more than 97%, whereas strains of different genotypes had 77.71-92.75% homology. The most divergent type was gB3.
  
  
  CONCLUSIONS
  Intra- and intergenotypic variations among strains were demonstrated either in individual or distinct patients. Intragenotypic variation in a person occurs possibly due mainly to a point mutation mechanism rather than reinfection of a new gB genotype.
authors.affiliation: Inter-Department of Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok, Thailand.
authors.forename: S
authors.initials: S
authors.lastname: Chantaraarphonkun
authors.forename: P
authors.initials: P
authors.lastname: Bhattarakosol
mesh_terms: D001483:Base Sequence; D003587:Cytomegalovirus / Q000145:classification* / Q000235:genetics*; D003586:Cytomegalovirus Infections / Q000821:virology*; D016172:DNA Fingerprinting; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D014644:Genetic Variation; D016679:Genome, Viral; D005838:Genotype; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013785:Thailand
chemical_list: D004279:DNA, Viral