Figure. Phylogenetic relationship of Plasmodium spp. inferred from small subunit ribosomal RNA sequences. Tree was reconstructed by using the neighbor-joining method. Boldface indicates those sequences derived from orangutans (VM40, VM82, VM88, and VS63) and those used by Reid et al. (12) in their phylogenetic analysis. Numerals on the branches are bootstrap percentages based on 1,000 replicates; only those >70% are shown. GenBank accession numbers are in brackets. Scale bar indicates nucleotide substitutions per site.