Plasmodium falciparum: typing of malaria parasites based on polymorphism of a novel multigene family.

Pf60.1, a marker recently isolated from the human malaria parasite Plasmodium falciparum, defines a large multigene family encoding antigens of 60 kDa, expressed by the blood stages (Carcy et al., Molecular and Biochemical Parasitology, 1994, 68, 221-233). Southern blotting showed that DNA from all strains and field isolates analyzed contained a large number of Pf60.1 copies. Considerable RFLP was observed. This diversity could be likewise visualized by analyzing PCR fragments amplified using primers derived from the Pf60.1 insert. Specific, multiple-band patterns were generated from laboratory strains, cloned lines, or wild isolates. This was further outlined after RsaI digestion of the PCR products. The sensitivity of this amplification was such that products could be visualized using a DNA amount representing less than one genome equivalent. Moreover, amplification was observed in some strains using a single primer, suggesting that some members of the Pf60.1 family are adjacent in an inverted orientation. This analysis confirmed the genetic similarity of a subset of laboratory strains. The results described here show that the extended diversity of this P. falciparum gene family provides a useful and sensitive PCR approach for strain typing.