title: Hepatitis C virus types 7, 8 and 9 should be classified as type 6 subtypes.
abstract: Tokita et al. reported the identification of hepatitis C virus type 7, 8 and 9 in Southeast Asia, based on the unweighed pair-group method with the arithmetic mean, a method that may not be appropriate when the nucleotide substitution rate is not constant over time. To determine more accurately the relationship of these proposed types 7, 8, and 9 with other types, a more appropriate approach, the neighbor-joining method, was applied to re-evaluate the phylogenetic relationship. A total of 660 HCV sequences, including the reported sequences, were collected from DNA databases. For every region, the nucleotide substitution rate was estimated by the 6-parameter method, and phylogenetic trees were constructed using the neighbor-joining method. The results of this analysis indicate that the newly proposed HCV types 7, 8 and 9 should be classified as type 6 subtypes. HCV type 6 appears to be diversified.
authors.affiliation: Second Department of Internal Medicine, Nagoya City University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Mizokami
authors.forename: T
authors.initials: T
authors.lastname: Gojobori
authors.forename: K
authors.initials: K
authors.lastname: Ohba
authors.forename: K
authors.initials: K
authors.lastname: Ikeo
authors.forename: X M
authors.initials: XM
authors.lastname: Ge
authors.forename: T
authors.initials: T
authors.lastname: Ohno
authors.forename: E
authors.initials: E
authors.lastname: Orito
authors.forename: J Y
authors.initials: JY
authors.lastname: Lau
mesh_terms: D019418:Evolution, Chemical; D016174:Hepacivirus / Q000145:classification*; D009711:Nucleotides / Q000737:chemistry*; D010802:Phylogeny
chemical_list: D009711:Nucleotides