title: Evidence for negative selection on the gene encoding rhoptry-associated protein 1 (RAP-1) in Plasmodium spp.
abstract: Assessing how natural selection, negative or positive, operates on genes with low polymorphism is challenging. We investigated the genetic diversity of orthologous genes encoding the rhoptry-associated protein 1 (RAP-1), a low polymorphic protein of malarial parasites that is involved in erythrocyte invasion. We applied evolutionary genetic methods to study the polymorphism in RAP-1 from Plasmodium falciparum (n=32) and Plasmodium vivax (n=6), the two parasites responsible for most human malaria morbidity and mortality, as well as RAP-1 orthologous in closely related malarial species found in non-human primates (NHPs). Overall, genes encoding RAP-1 are highly conserved in all Plasmodium spp. included in this investigation. We found no evidence for natural selection, positive or negative, acting on the gene encoding RAP-1 in P. falciparum or P. vivax. However, we found evidence that the orthologous genes in non-human primate parasites (Plasmodium cynomolgi, Plasmodium inui, and Plasmodium knowlesi) are under purifying (negative) selection. We discuss the importance of considering negative selection while studying genes encoding proteins with low polymorphism and how selective pressures may differ among orthologous genes in closely related malarial parasites species.
authors.affiliation: School of Life Sciences, Arizona State University, PO Box 874501, Tempe, AZ 85287-4501, United States.
authors.forename: M Andreína
authors.initials: MA
authors.lastname: Pacheco
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Ryan
authors.forename: Amanda C
authors.initials: AC
authors.lastname: Poe
authors.forename: Leonardo
authors.initials: L
authors.lastname: Basco
authors.forename: Venkatachalam
authors.initials: V
authors.lastname: Udhayakumar
authors.forename: Williams E
authors.initials: WE
authors.lastname: Collins
authors.forename: Ananias A
authors.initials: AA
authors.lastname: Escalante
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D010961:Plasmodium / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D012641:Selection, Genetic; D016415:Sequence Alignment
chemical_list: D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C065352:rhoptry associated protein, Plasmodium