Principal component analysis (PCA) of population structure of P . vivax. Plots show the three first principal components. Each circle or square represents a parasite isolate or strain and the color is assigned according to the geographic origin of parasites: green circles, Granada; red circles, Plácido de Castro; open circles, Porto Velho (all samples from Brazil are represented with circles); pink squares, Cambodia; blue squares, Sri Lanka; light brown squares, Vietnam (all samples from Asia are represented with squares). The strains Salvador I and Belém are denoted by orange and black circles, respectively. The number of circles or squares plotted in the panels does not correspond to the total number of parasite samples analyzed (Additional file 1 Table S1) because some of them had identical haplotypes and, therefore, had identical PCA coordinates. Upper panel, plot of the first two principal components; Lower panel, plot of the first and third principal components.