Major merozoite surface protein-3α alleles identified by PCR and digestion with Alu I and Hha I restriction enzymes in the Plasmodium vivax population from Bannu district, Pakistan. Lane 1 = 50 bp, 2 = 1 Kb, and 3 = 100 bp DNA marker. A, B, C = Undigested PCR products. A1, A2 ... are allele types revealed by digestion of the respective PCR products with Alu I, while a1, a2 ... are the allele types obtained by digestion with Hha I, and M = mixed genotype. Frequencies of these alleles are presented in Table 2.