title: Comparative sequence analysis of domain I of Plasmodium falciparum apical membrane antigen 1 from Saudi Arabia and worldwide isolates.
abstract: The apical membrane antigen 1 of Plasmodium falciparum (PfAMA1) plays a crucial role in erythrocyte invasion and is a target of protective antibodies. Although domain I of PfAMA1 has been considered a promising vaccine component, extensive sequence diversity in this domain could compromise an effective vaccine design. To explore the extent of sequence diversity in domain I of PfAMA1, P. falciparum-infected blood samples from Saudi Arabia collected between 2007 and 2009 were analyzed and compared with those from worldwide parasite populations. Forty-six haplotypes and a novel codon change (M190V) were found among Saudi Arabian isolates. The haplotype diversity (0.948±0.004) and nucleotide diversity (0.0191±0.0008) were comparable to those from African hyperendemic countries. Positive selection in domain I of PfAMA1 among Saudi Arabian parasite population was observed because nonsynonymous nucleotide substitutions per nonsynonymous site (dN) significantly exceeded synonymous nucleotide substitutions per synonymous site (dS) and Tajima's D and its related statistics significantly deviated from neutrality in the positive direction. Despite a relatively low prevalence of malaria in Saudi Arabia, a minimum of 17 recombination events occurred in domain I. Genetic differentiation was significant between P. falciparum in Saudi Arabia and parasites from other geographic origins. Several shared or closely related haplotypes were found among parasites from different geographic areas, suggesting that vaccine derived from multiple shared epitopes could be effective across endemic countries.
authors: Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia; Department of Microbiology and Immunology, Alfaisal University College of Medicine, Riyadh, Saudi Arabia. Electronic address: aqahtani@kfshrc.edu.sa.
authors: Ahmed A
authors: AA
authors: Al-Qahtani
authors: Tropical Medicine Research Institute, National Centre for Research, Sudan; Department of Biology, Faculty of Science, University of Hail, Hail, Saudi Arabia.
authors: Abdel-Muhsin A
authors: AA
authors: Abdel-Muhsin
authors: Department of Biology, Faculty of Science, King Khalid University, Abha, Saudi Arabia.
authors: Saad M Bin
authors: SMB
authors: Dajem
authors: National Center for Vector-Borne Diseases, Ministry of Health, Jazan, Saudi Arabia.
authors: Adel Ali H
authors: AAH
authors: AlSheikh
authors: Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia.
authors: Marie Fe F
authors: MFF
authors: Bohol
authors: Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia; Department of Microbiology and Immunology, Alfaisal University College of Medicine, Riyadh, Saudi Arabia.
authors: Mohammed N
authors: MN
authors: Al-Ahdal
authors: Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
authors: Chaturong
authors: C
authors: Putaporntip
authors: Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand. Electronic address: jongwutiwes@gmail.com.
authors: Somchai
authors: S
authors: Jongwutiwes
mesh_terms: D000293:Adolescent; D000328:Adult; D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics*; D005260:Female; D014644:Genetic Variation; D006239:Haplotypes; D006801:Humans; D016778:Malaria, Falciparum / Q000453:epidemiology* / Q000469:parasitology*; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D010802:Phylogeny; D010963:Plasmodium falciparum / Q000145:classification / Q000235:genetics*; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics*; D011995:Recombination, Genetic; D012529:Saudi Arabia / Q000453:epidemiology; D017422:Sequence Analysis, DNA; D055815:Young Adult
chemical_list: D000953:Antigens, Protozoan; D008565:Membrane Proteins; D015800:Protozoan Proteins; C090077:apical membrane antigen I, Plasmodium
keywords: Apical membrane antigen 1; Natural selection; Plasmodium falciparum; Population genetics; Saudi Arabia; Sequence analysis