The mosquito that first injected Homo sapiens with the malaria parasite Plasmodium falciparum didn’t pick it up from humans’ closest primate relative, the chimpanzee, but from the western gorilla, new research suggests. The primary cause of malaria in humans, P. falciparum is most closely related to another species of Plasmodium that infects gorillas, scientists report in the Sept. 23 Nature.
The discovery vindicates chimpanzees: Previous research suggested that the human-infecting
was most closely related to the chimp-infecting version of the parasite,
. This notion fit with a tidy picture of host-parasite evolution, suggesting the malaria parasite lineage split at the same time as the chimp-human lineage. But
DNA collected from more than 2,500 fecal samples of eastern gorillas, western gorillas, bonobos and chimpanzees points to western gorillas as the source. The evidence also suggests the jump happened only once, says study leader Beatrice Hahn of the University of Alabama at Birmingham. As for the time frame of that event, scientists are still scratching their heads.