THE POLYMORPHIC SUBTELOMERIC REGIONS OF PLASMODIUM-FALCIPARUM CHROMOSOMES CONTAIN ARRAYS OF REPETITIVE SEQUENCE ELEMENTS

The human malaria parasite Plasmodium falciparum exhibits a high degre e of chromosomal polymorphism, which may contribute to its ability to evade host defenses. The analysis of parasite chromosomes has revealed that these poly morphisms are confined to the subtelomeric regions, w hich are transcriptionally silent and contain repetitive sequence elem ents. Several subtelomeric repetitive elements have been isolated and mapped by using P. falciparum yeast artificial chromosome (YAC) clones . Structural analysis of parasite telomeric and subtelomeric YAC clone s demonstrated that these repetitive elements are conserved between P. falciparum chromosome ends. We suggest that these subtelomeric elemen ts promote chromosome pairing in P. falciparum and facilitate meiotic recombination and gene conversion between telomere-proximal genes.