Proof of intragenic recombination in Plasmodium falciparum.

Intragenic recombination in the merozoite surface protein MSP-1 of Plasmodium falciparum has been demonstrated in a cross between two cloned lines (3D7 and HB3) of this species. Following passage of a mixture of the clones through mosquitoes, uncloned progeny were examined by PCR for molecules containing sequences of both parent MSP-1 alleles. A recombinant molecule possessing both 3D7 and HB3 sequences has been obtained. Such molecules were not obtained from artificial mixtures of the blood forms of each clone. It is concluded that the novel allele was formed by a recombination event during meiosis of a hybrid 3D7/HB3 zygote.