Open AccessGenetic dissociation of three antigenic genes in Plasmodium ovale curtisi and Plasmodium ovale wallikeri
Author(s) -
Naowarat Saralamba,
François Nosten,
Colin J. Sutherland,
Ana Paula Arez,
Georges Snounou,
Nicholas J. White,
Nicholas Day,
Arjen M. Dondorp,
Mallika Imwong
Publication year - 2019
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0217795
Subject(s) - biology , plasmodium ovale , genetics , gene , virology , plasmodium falciparum , malaria , plasmodium vivax , immunology
Plasmodium ovale curtisi and Plasmodium ovale wallikeri are two sympatric human malaria species prevalent in Africa, Asia and Oceania. The reported prevalence of both P . ovale spp. was relatively low compared to other malaria species, but more sensitive molecular detection techniques have shown that asymptomatic low-density infections are more common than previously thought. Whole genome sequencing of both P . ovale spp. revealed genetic dissociation between P . ovale curtisi and P . ovale wallikeri suggesting a species barrier. In this study we further evaluate such a barrier by assessing polymorphisms in the genes of three vaccine candidate surface protein: circumsporozoite protein/ thrombospondin-related anonymous-related protein ( ctrp ), circumsporozoite surface protein ( csp ) and merozoite surface protein 1 ( msp1 ). The complete coding sequence of ctrp and csp , and a partial fragment of msp1 were isolated from 25 P . ovale isolates and compared to previously reported reference sequences. A low level of nucleotide diversity (Pi = 0.02–0.10) was observed in all three genes. Various sizes of tandem repeats were observed in all ctrp , csp and msp1 genes. Both tandem repeat unit and nucleotide polymorphism in all three genes exhibited clear dimorphism between P . ovale curtisi and P . ovale wallikeri , supporting evidence of non-recombination between these two species.