title: Genetic diversity and population structure of genes encoding vaccine candidate antigens of Plasmodium vivax.
abstract: BACKGROUND
  A major concern in malaria vaccine development is genetic polymorphisms typically observed among Plasmodium isolates in different geographical areas across the world. Highly polymorphic regions have been observed in Plasmodium falciparum and Plasmodium vivax antigenic surface proteins such as Circumsporozoite protein (CSP), Duffy-binding protein (DBP), Merozoite surface protein-1 (MSP-1), Apical membrane antigen-1 (AMA-1) and Thrombospondin related anonymous protein (TRAP).
  
  
  METHODS
  Genetic variability was assessed in important polymorphic regions of various vaccine candidate antigens in P. vivax among 106 isolates from the Amazon Region of Loreto, Peru. In addition, genetic diversity determined in Peruvian isolates was compared to population studies from various geographical locations worldwide.
  
  
  RESULTS
  The structured diversity found in P. vivax populations did not show a geographic pattern and haplotypes from all gene candidates were distributed worldwide. In addition, evidence of balancing selection was found in polymorphic regions of the trap, dbp and ama-1 genes.
  
  
  CONCLUSIONS
  It is important to have a good representation of the haplotypes circulating worldwide when implementing a vaccine, regardless of the geographic region of deployment since selective pressure plays an important role in structuring antigen diversity.
authors.affiliation: Parasitology Program, Naval Medical Research Unit No, 6, Lima, Peru.
authors.forename: Stella M
authors.initials: SM
authors.lastname: Chenet
authors.forename: Lorena L
authors.initials: LL
authors.lastname: Tapia
authors.forename: Ananias A
authors.initials: AA
authors.lastname: Escalante
authors.forename: Salomon
authors.initials: S
authors.lastname: Durand
authors.forename: Carmen
authors.initials: C
authors.lastname: Lucas
authors.forename: David J
authors.initials: DJ
authors.lastname: Bacon
mesh_terms: D000595:Amino Acid Sequence; D000940:Antigenic Variation / Q000235:genetics / Q000276:immunology; D000953:Antigens, Protozoan / Q000235:genetics* / Q000276:immunology; D001208:Asia; D006239:Haplotypes; D007843:Latin America; D017780:Malaria Vaccines / Q000276:immunology*; D008969:Molecular Sequence Data; D044349:Oceania; D058974:Phylogeography; D010966:Plasmodium vivax / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D011110:Polymorphism, Genetic / Q000276:immunology*
chemical_list: D000953:Antigens, Protozoan; D017780:Malaria Vaccines