Plasmodium falciparum accompanied the human expansion out of Africa.
Plasmodium falciparum is distributed throughout the tropics and is responsible for an estimated 230 million cases of malaria every year, with a further 1.4 billion people at risk of infection. Little is known about the genetic makeup of P. falciparum populations, despite variation in genetic diversity being a key factor in morbidity, mortality, and the success of malaria control initiatives. Here we analyze a worldwide sample of 519 P. falciparum isolates sequenced for two housekeeping genes (63 single nucleotide polymorphisms from around 5000 nucleotides per isolate). We observe a strong negative correlation between within-population genetic diversity and geographic distance from sub-Saharan Africa (R(2) = 0.95) over Africa, Asia, and Oceania. In contrast, regional variation in transmission intensity seems to have had a negligible impact on the distribution of genetic diversity. The striking geographic patterns of isolation by distance observed in P. falciparum mirror the ones previously documented in humans and point to a joint sub-Saharan African origin between the parasite and its host. Age estimates for the expansion of P. falciparum further support that anatomically modern humans were infected prior to their exit out of Africa and carried the parasite along during their colonization of the world.
Tanabe
Kazuyuki
K
Laboratory of Malariology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan. kztanabe@biken.osaka-u.ac.jp
Mita
Toshihiro
T
Jombart
Thibaut
T
Eriksson
Anders
A
Horibe
Shun
S
Palacpac
Nirianne
N
Ranford-Cartwright
Lisa
L
Sawai
Hiromi
H
Sakihama
Naoko
N
Ohmae
Hiroshi
H
Nakamura
Masatoshi
M
Ferreira
Marcelo U
MU
Escalante
Ananias A
AA
Prugnolle
Franck
F
Björkman
Anders
A
Färnert
Anna
A
Kaneko
Akira
A
Horii
Toshihiro
T
Manica
Andrea
A
Kishino
Hirohisa
H
Balloux
Francois
F
D000818:Animals; D001483:Base Sequence; D001499:Bayes Theorem; D017931:DNA Primers / Q000235:genetics; D003710:Demography; D004641:Emigration and Immigration; D014644:Genetic Variation; D005828:Genetics, Population; D005843:Geography; D006801:Humans; D016778:Malaria, Falciparum / Q000635:transmission*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics* / Q000502:physiology; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011157:Population Dynamics; D017422:Sequence Analysis, DNA
D017931:DNA Primers