Chromosomal polymorphism and sexual differentiation in Plasmodium.
The correlation observed in several instances between the loss of ability to produce gametocytes and chromosomal rearrangements, prompted us to investigate in further detail the molecular bases of chromosomal polymorphism in Plasmodium. Generation of polymorphic karyotypes in Plasmodium involves important rearrangements, mostly occurring in subtelomeric position. Detailed analysis on the organisation of these regions have been carried out on the rodent malaria P. berghei and the human malaria P. falciparum. A 2.3kb sequence, tandemly organised in long clusters is shared by many P. berghei chromosomal ends. Variations in the copy number of this "module" account for most of the observed polymorphisms. In a P. falciparum cloned line (3D7) a common region spanning at least 40 kb, is present. It does not contain any repetitive structure other than the rep20 cluster, that appears to be completely contained within the common region. Notwithstanding the structural differences, human and rodent Plasmodia share the common feature of possessing long subtelomeric regions showing, thus, a homology between the different chromosomes.
Ponzi
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M
Laboratorio di Biologia Cellulare, Istituto Superiore di Sanità, Roma, Italia.
Alano
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P
Scotti
R
R
Roca
L
L
D000818:Animals; D002869:Chromosome Aberrations; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D002875:Chromosomes / Q000648:ultrastructure*; D016054:DNA, Protozoan / Q000235:genetics; D005260:Female; D008297:Male; D010962:Plasmodium berghei / Q000235:genetics* / Q000502:physiology; D010963:Plasmodium falciparum / Q000235:genetics* / Q000502:physiology; D011110:Polymorphism, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D013045:Species Specificity
D016054:DNA, Protozoan