Phylogenetic analysis of (A) capsid (376 nt) and (B) polymerase (289 nt) sequences of Mc10, C12, and additional strains in GenBank. Sapovirus capsid sequences were classified on the basis of the scheme of Okada et al. (10). Two unclassified strains, Mex340/1990 and Cruise ship/00, were assigned SG-II-(d) and SG-II-(e). The asterisks indicate noncontinuous polymerase-capsid sequences. The numbers on each branch indicate the bootstrap values for the genotype. Bootstrap values of >950 were considered statistically significant for the grouping (6). The scale represents nucleotide substitutions per site. GenBank accession no. for the reference strains are as follows: Chiba/000671T/1999, AJ412805; Chiba/990727S/1999, AJ412795; Chiba/991172S/1999, AJ412797; Mc114, AY237422; Cruise ship/00, AY289804 and AY157863; Cowden, AF182760; Houston/27/90/US, U95644; Mc2, AY237419; Mc10, AY237420; Mex340/1990, AF435809 and AF435812; Mex14917/00, AF435813 and AF35810; Sapporo/82/Japan, U65427; and Stockholm/318/97/SE, AF194182.