Figure 2. An overview of the genetic relationships of human enterovirus 71 (HEV71) strains isolated from 1970 through 2002. Unrooted cladogram shows the genogroup relationships of HEV71 based on an alignment of the partial VP4 gene (nucleotide positions 744–950) consensus sequences for genogroups B1, B2, B3, B4, C1, C2, and C3. The complete VP4 gene sequence of the prototype strain BrCr-CA-70 (30) was used as an outgroup in the analysis. The bootstrap values in 1,000 pseudoreplicates for major lineages within the dendrogram are shown as percentages. The marker denotes a measurement of relative phylogenetic distance.