Plasmodium falciparum: characterization of a 0.7-kbp, moderately repetitive sequence.

Abstract A 692-bp-long repetitive sequence of Plasmodium falciparum was cloned. Two contiguous repeats were sequenced. The homology between them was 85%, the differences being due only to base replacements. The sequence was found 60 times repeated in the genome and was detected in 11 of 14 chromosomes. When used as a probe, the cloned fragment detected the parasite with the same sensitivity the 21-bp repeat (pRepHind) did. PCR amplification detected 0.02 pg of DNA, equivalent to a single parasite, in strains from America, Asia, and Africa. The restriction patterns were polymorphic and different among the strains. Analysis of λ EMBL clones that contain the repetitive sequence confirms that it is present in various genomic contexts and is located subtelomerically.