Phylogeny of the malarial genus Plasmodium, derived from rRNA gene sequences

Ananias A. Escalante, Francisco J. Ayala

Research output: Contribution to journalArticlepeer-review

269 Scopus citations


Malaria is among mankind's worst scourges, affecting many millions of people, particularly in the tropics. Human malaria is caused by several species of Plasmodium, a parasitic protozoan. We analyze the small subunit rRNA gene sequences of 11 Plasmodium species, including three parasitic to humans, to infer their evolutionary relationships. Plasmodium falciparum, the most virulent of the human species, is closely related to Plasmodium reichenowi, which is parasitic to chimpanzee. The estimated time of divergence of these two Plasmodium species is consistent with the time of divergence (6-10 million years ago) between the human and chimpanzee lineages. The falciparum-reichenowi clade is only remotely related to two other human parasites, Plasmodium malariae and Plasmodium vivax, which are also only remotely related to each other. Thus, the parasitic associations of the Plasmodium species with their human hosts are phylogenetically independent. The remote phylogenetic relationship between the two bird parasites, Plasmodium gallinaceum and Plasmodium lophurae, and any of the human parasites provides no support for the hypothesis that infection by Plasmodium falciparum is a recent acquisition of humans, possibly coincident with the onset of agriculture.

Original languageEnglish (US)
Pages (from-to)11373-11377
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number24
StatePublished - Nov 22 1994
Externally publishedYes


  • Plasmodium falciparum
  • host switch
  • human malaria
  • small subunit rRNA

ASJC Scopus subject areas

  • General


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