PCR-RFLP analysis of PvMSP-3α gene in Plasmodium vivax samples obtained from four Asian populations. a: Examples of major alleles and mixed genotypes; and b: reperesentive samples showing various restriction digestion patterns and classification of alleles. Upper panel, undigested PCR products, and Lower panel, PCR products digested with Hha I. Lane marker: M – DNA size marker; A, B, C – allele types; M1 and M2 - mixed strain infections; A1, A2, …A10, B1, B2… - alleles identified by PCR-RFLP.