P¹/P² genotyping assays. (A) PCR-ASP: lanes 1, 3, and 5 show the P¹-specific amplification, and lanes 2, 4, and 6 show P²-specific amplicons (size indicated by an arrow). The upper band is the JK blood group gene-derived control band present in both JK*A and JK*B and found in all individuals tested so far including those with the Jk(a-b-) phenotype. Lanes 1 and 2, a P¹ homozygous sample; lanes 3 and 4, a P¹P² heterozygous sample; and lanes 5 and 6, a P² homozygous sample. ϕX 174 DNA/HinfI was used as size marker (M). (B) PCR-RFLP: fragments amplified from exon 2a digested with NlaIII and run on a 4% agarose gel. Lane 1 shows the undigested P¹P¹ sample; lane 2 shows the fully digested P²P² sample; and lane 3 shows the P¹P² sample with both digested and undigested fragments. ϕX 174 DNA/HinfI was used as size marker (M). (C) AD by the SNP genotyping assay: 25 samples to be typed and 3 control samples with known genotype (one with each genotype) were run in triplicate. Water was used as negative control (indicated by x). All samples clustered in 3 well-defined and separate areas (circles for P¹P¹; triangles for P¹P²; and diamonds for P²P² samples).