title: Heterogeneous genetic diversity pattern in Plasmodium vivax genes encoding merozoite surface proteins (MSP) -7E, -7F and -7L.
abstract: BACKGROUND
  The msp-7 gene has become differentially expanded in the Plasmodium genus; Plasmodium vivax has the highest copy number of this gene, several of which encode antigenic proteins in merozoites.
  
  
  METHODS
  DNA sequences from thirty-six Colombian clinical isolates from P. vivax (pv) msp-7E, -7F and -7L genes were analysed for characterizing and studying the genetic diversity of these pvmsp-7 members which are expressed during the intra-erythrocyte stage; natural selection signals producing the variation pattern so observed were evaluated.
  
  
  RESULTS
  The pvmsp-7E gene was highly polymorphic compared to pvmsp-7F and pvmsp-7L which were seen to have limited genetic diversity; pvmsp-7E polymorphism was seen to have been maintained by different types of positive selection. Even though these copies seemed to be species-specific duplications, a search in the Plasmodium cynomolgi genome (P. vivax sister taxon) showed that both species shared the whole msp-7 repertoire. This led to exploring the long-term effect of natural selection by comparing the orthologous sequences which led to finding signatures for lineage-specific positive selection.
  
  
  CONCLUSIONS
  The results confirmed that the P. vivax msp-7 family has a heterogeneous genetic diversity pattern; some members are highly conserved whilst others are highly diverse. The results suggested that the 3'-end of these genes encode MSP-7 proteins' functional region whilst the central region of pvmsp-7E has evolved rapidly. The lineage-specific positive selection signals found suggested that mutations occurring in msp-7s genes during host switch may have succeeded in adapting the ancestral P. vivax parasite population to humans.
authors.forename: Diego
authors.initials: D
authors.lastname: Garzón-Ospina
authors.forename: Johanna
authors.initials: J
authors.lastname: Forero-Rodríguez
authors.affiliation: Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 No, 26-20, Bogotá, DC, Colombia. mapatarr.fidic@gmail.com.
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Patarroyo
mesh_terms: D016000:Cluster Analysis; D003105:Colombia; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D014644:Genetic Variation; D006801:Humans; D016780:Malaria, Vivax / Q000469:parasitology; D008565:Membrane Proteins / Q000235:genetics*; D052940:Merozoites; D008969:Molecular Sequence Data; D010802:Phylogeny; D010966:Plasmodium vivax / Q000235:genetics* / Q000302:isolation & purification; D015800:Protozoan Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
chemical_list: D016054:DNA, Protozoan; D008565:Membrane Proteins; D015800:Protozoan Proteins; C439571:merozoite surface protein 7, Plasmodium