FIG. 3.

Phylogenetic tree constructed by the neighbor-joining method based on the partial nucleotide sequence (301 nt) of the ORF2 region of 73 human and swine isolates. In addition to 21 reported human and swine HEV isolates of genotypes I to IV whose entire or nearly entire sequence is known, 40 reported isolates of genotype III or IV whose partial sequence of 301, 304, 346, 348, 421, 1,402, or 1,497 nt has been determined were included for comparison. They are deposited under accession nos. AB073910, AB073911, AF103940, AF117275 to AF117281, AF134812, AF134916, AF134917, AF151962, AF151963, AF195061 to AF195063, AF296162 to AF296167, AF302068, AJ344171, AJ344172, AJ344177, AJ344179 to AJ344181, AJ344183 to AJ344186, AJ344188, and AJ344191 to AJ344194. All except one of the human and swine HEV strains isolated in Japan are segregated into one of three groups (groups A to C), as indicated by the shaded circles; the one exception is swine isolate swJ791, which is close to the Spanish strains (Sp1, Sp2, and Sp3). Bootstrap values of >70% are indicated for the major nodes as a percentage of the data obtained from 1,000 resamplings.