Neighbor-joining tree based on the asexually transcribed SSU rRNA sequences displaying the phylogenetic position of isolate A1 in this study in relation to other Plasmodium knowlesi isolates (AY327549-AY327556 from humans, and L07560, U72542, and AY327557 from monkeys) and Plasmodium fragile (M61722). The tree was constructed with Kimura's two-parameter distance. including transitions and transversions as implemented in the MEGA version 2.1 software. Bootstrap percentages more than 50% based on