Plasmodium falciparum: Eco RI site Polymorphism in the Genome of a Parasite Clone Grown In Vitro in Presence of Pyrimethamine

The restriction fragment length polymorphisms (RFLPs) patterns of the increasing number of dihydrofolate reductase-thymidylate synthase (dhfr-ts) gene copy in the parasite genome were analyzed. The RFLPs profile of pyrimethamine resistant clone line of Plasmodium falciparum, T9/94RC17, grown in vitro in the presence of pyrimethamine showed the amplification of this gene including the 5 / and 3 / flanking region outside the gene. Moreover, one of the resistant progenies, T9/94RC17 Py 10 -7 , had two extra small gene fragments in the DNA profile. An error during DNA replication under drug pressure condition or point mutation that caused new restriction site nearer to the gene or DNA deletion may be a cause of this finding. At 10 -7 M of drug may be a crucial condition for parasite adaptation to survive and has higher resistant to this drug.