title: Genetic polymorphism and natural selection of Duffy binding protein of Plasmodium vivax Myanmar isolates.
abstract: BACKGROUND
  Plasmodium vivax Duffy binding protein (PvDBP) plays an essential role in erythrocyte invasion and a potential asexual blood stage vaccine candidate antigen against P. vivax. The polymorphic nature of PvDBP, particularly amino terminal cysteine-rich region (PvDBPII), represents a major impediment to the successful design of a protective vaccine against vivax malaria. In this study, the genetic polymorphism and natural selection at PvDBPII among Myanmar P. vivax isolates were analysed.
  
  
  METHODS
  Fifty-four P. vivax infected blood samples collected from patients in Myanmar were used. The region flanking PvDBPII was amplified by PCR, cloned into Escherichia coli, and sequenced. The polymorphic characters and natural selection of the region were analysed using the DnaSP and MEGA4 programs.
  
  
  RESULTS
  Thirty-two point mutations (28 non-synonymous and four synonymous mutations) were identified in PvDBPII among the Myanmar P. vivax isolates. Sequence analyses revealed that 12 different PvDBPII haplotypes were identified in Myanmar P. vivax isolates and that the region has evolved under positive natural selection. High selective pressure preferentially acted on regions identified as B- and T-cell epitopes of PvDBPII. Recombination may also be played a role in the resulting genetic diversity of PvDBPII.
  
  
  CONCLUSIONS
  PvDBPII of Myanmar P. vivax isolates displays a high level of genetic polymorphism and is under selective pressure. Myanmar P. vivax isolates share distinct types of PvDBPII alleles that are different from those of other geographical areas. These results will be useful for understanding the nature of the P. vivax population in Myanmar and for development of PvDBPII-based vaccine.
authors.affiliation: Department of Parasitology and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju 660-751, Korea.
authors.forename: Hye-Lim
authors.initials: HL
authors.lastname: Ju
authors.forename: Jung-Mi
authors.initials: JM
authors.lastname: Kang
authors.forename: Sung-Ung
authors.initials: SU
authors.lastname: Moon
authors.forename: Jung-Yeon
authors.initials: JY
authors.lastname: Kim
authors.forename: Hyeong-Woo
authors.initials: HW
authors.lastname: Lee
authors.forename: Khin
authors.initials: K
authors.lastname: Lin
authors.forename: Woon-Mok
authors.initials: WM
authors.lastname: Sohn
authors.forename: Jin-Soo
authors.initials: JS
authors.lastname: Lee
authors.forename: Tong-Soo
authors.initials: TS
authors.lastname: Kim
authors.forename: Byoung-Kuk
authors.initials: BK
authors.lastname: Na
mesh_terms: D000953:Antigens, Protozoan / Q000235:genetics*; D003001:Cloning, Molecular; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D016780:Malaria, Vivax / Q000469:parasitology; D008969:Molecular Sequence Data; D002052:Myanmar; D010966:Plasmodium vivax / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics*; D011956:Receptors, Cell Surface / Q000235:genetics*; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA
chemical_list: D000953:Antigens, Protozoan; D016054:DNA, Protozoan; C066001:Duffy antigen binding protein, Plasmodium; D015800:Protozoan Proteins; D011956:Receptors, Cell Surface