Figure 1

PCR-RFLP of the pfdhfr gene, amplified region of M3-F/primers. BsrI cleaved the 522 bp fragment into 190 and 332 bp indication of 108asn mutation (A). DraI detect 164leu mutations producing 28, 107, 171 and 245 bp fragments for wild type and 107, 143 and 245 bp for mutant (B). Digestion with NlaIII produce 53, 93 and 376 bp for wild type and 146 and 245 bp for mutant at codon 16 (C) and digestion with Tsp5091 yielded 55, 65, 120, and 153 bp fragments for wild type and 55, 65, 120 and 218 bp fragments for mutant for detection on polymorphism at codon 51 (D). Lane L: DNA ladder of Agilent DNA 1000 Kit (Agilent Technologies, Molecular Probes Inc, USA), The controls are in Lane 1 and 2: A: Lane 1: Plasmodium falciparum KI strain (mutant); Lane 2: P. falciparum T9.96 strain (wild type); Lane 3–9: field samples from Kalabakan; well 10: PCR negative control (no DNA was added to the PCR reaction). B and C: Lane 1: Plasmodium falciparum KI strain (wild type); Lane 2: P. falciparum T9.96 strain (wild type); Lane 3–9: field samples from Kalabakan; well 10: PCR negative control (no DNA was added to the PCR reaction). D: Lane 1: Plasmodium falciparum KI strain (wild type); Lane 2: P. falciparum W2 strain (mutant) Lane 3–9: field samples from Kalabakan; well 10: PCR negative control (no DNA was added to the PCR reaction).