Figure 5From: Differentiating Plasmodium falciparum alleles by transforming Cartesian X,Y data to polar coordinatesControl experiment using sample mixtures of known allelic ratios to assess the sensitivity of the histogram segmentation analysis. The LDR-FMA assay was performed for chr1SNP (CombinedSNP.MAL1.1085, PlasmoDB SNP identifier [13]) on 264 samples collected in PNG (blue dots). The polar coordinate histogram method generated diagnostic thresholds (black solid lines) and 95% confidence intervals (red dotted lines). The LDR-FMA assay was performed separately for the same SNP on 34 mixtures of control strains with known genotypes (HB3, allele-T; K1, allele-A) at DNA concentrations ranging from 1:1 to 99:1 (major allele:minor allele, cross-hair symbols) along with a pure sample of each strain and a blank. Samples correctly called as "mixed" had concentration ratios ranging from 1:1 to as high as 15:1. All samples with major:minor allele ratios of 29:1 or higher were misclassified as "single strain infections". Of samples with major:minor allele ratios of 9:1 or smaller, 95% were called correctly (19 of 20); of those with ratios 10:1 or smaller, over 90% were called correctly (22 of 24).Back to article page