FIG. 1.

Phylogenetic tree constructed by the neighbor-joining method based on the partial nucleotide sequence of the S gene (396 nt) of 74 HBV isolates, using a woolly HBV (AF046996) as an outgroup. In addition to the 22 Mongolian isolates found in the present study (which are indicated in boldface type for visual clarity), 52 reported HBV isolates of genotypes A to H whose entire sequence is known were included for comparison. Each reported isolate is indicated with the accession number followed by the name of the country where it was isolated. Asterisks denote Mongolian HBV strains that were isolated from serum samples that were also positive for HDV RNA. Bootstrap values are indicated for the major nodes as a percentage of the data obtained from 1,000 resamplings.