FIG. 2.

Neighbor-joining tree depicting the phylogenetic relationships among HCV reference sequences and sequences from the R1 strain. Trees were constructed for a 3,430-nucleotide fragment within the 5′ UTR to the NS2 gene (A) and a 5,390-nucleotide fragment within the NS3 region to the NS5B gene (B) by using the MEGA program with the Tamura-Nei model with gamma-corrected rates. Confidence values calculated by bootstrap analysis (100 replicates) are indicated at the major branching points. Reference sequences from HCV strains from the Los Alamos HCV sequence database are listed by their accession numbers.