Plasmodium falciparum: genetic stability of the Uganda Palo Alto strain propagated in the squirrel monkey (Saimiri sciureus).

The Uganda Palo Alto strain of Plasmodium falciparum has been extensively used in several laboratories to infect Saimiri monkeys. In the study reported here three distinct lines derived by parallel serial blood transfers from a single 10-year-old passage of the Palo Alto strain were examined for genetic diversity using the polymerase chain reaction and restriction mapping techniques. A comparison of the PF 11.1, P190, MSA2, S-Ag, and KAHRP genes indicates that these parasite lines are apparently homogeneous and stable. Nevertheless, microheterogeneity was observed with molecular probes which are known to easily detect restriction fragment length polymorphisms (rep 20 and telomeric probes). These data show that the genetic characters of the strain can be considered monomorphic and are conserved after multiple passages in the squirrel monkey.