May 21, 2005

Origin of Plasmodium parasites

A new study investigated the time depth of P. vivax and P. falciparum, two parasites implicated in human malaria.

Molecular Biology and Evolution (advance publication)

Mitochondrial Genome Sequences Support Ancient Population Expansion in Plasmodium vivax

Somchai Jongwutiwes et al.


Examination of nucleotide diversity in 106 mitochondrial genomes of the most geographically widespread human malaria parasite, Plasmodium vivax, revealed a level of diversity similar to, but slightly higher than, that seen in the virulent human malaria parasite Plasmodium falciparum. The pairwise distribution of nucleotide differences among mitochondrial genome sequences supported the hypothesis that both of these parasites underwent ancient population expansions. We estimated the age of the most recent common ancestor (MRCA) of the mitochondrial genomes of both P. vivax and P. falciparum at around 200,000-300,000 years ago. This is close to previous estimates of the time of the human mitochondrial MRCA and the origin of modern Homo sapiens, consistent with the hypothesis that both of these Plasmodium species were parasites of the hominid lineage before the origin of modern Homo sapiens and that their population expansion coincided with the population expansion of their host.


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