Unraveling Haplotype Diversity of the Apical Membrane Antigen-1 Gene in Plasmodium falciparum Populations in Thailand
10.3347/kjp.2018.56.2.153
- Author:
Lalita LUMKUL
1
;
Vorthon SAWASWONG
;
Phumin SIMPALIPAN
;
Morakot KAEWTHAMASORN
;
Pongchai HARNYUTTANAKORN
;
Sittiporn PATTARADILOKRAT
Author Information
1. Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand. Sittiporn.P@Chula.ac.th
- Publication Type:Original Article
- Keywords:
Plasmodium falciparum;
genetic polymorphism;
human malaria;
vaccine;
antigen
- MeSH:
Amino Acid Sequence;
Base Sequence;
Cambodia;
DNA;
Erythrocytes;
Gene Flow;
Haplotypes;
Humans;
Laos;
Malaria;
Malaria Vaccines;
Membranes;
Myanmar;
Parasites;
Plasmodium falciparum;
Plasmodium;
Polymerase Chain Reaction;
Polymorphism, Genetic;
Thailand;
Trees
- From:The Korean Journal of Parasitology
2018;56(2):153-165
- CountryRepublic of Korea
- Language:English
-
Abstract:
Development of an effective vaccine is critically needed for the prevention of malaria. One of the key antigens for malaria vaccines is the apical membrane antigen 1 (AMA-1) of the human malaria parasite Plasmodium falciparum, the surface protein for erythrocyte invasion of the parasite. The gene encoding AMA-1 has been sequenced from populations of P. falciparum worldwide, but the haplotype diversity of the gene in P. falciparum populations in the Greater Mekong Subregion (GMS), including Thailand, remains to be characterized. In the present study, the AMA-1 gene was PCR amplified and sequenced from the genomic DNA of 65 P. falciparum isolates from 5 endemic areas in Thailand. The nearly full-length 1,848 nucleotide sequence of AMA-1 was subjected to molecular analyses, including nucleotide sequence diversity, haplotype diversity and deduced amino acid sequence diversity and neutrality tests. Phylogenetic analysis and pairwise population differentiation (F( st) indices) were performed to infer the population structure. The analyses identified 60 single nucleotide polymorphic loci, predominately located in domain I of AMA-1. A total of 31 unique AMA-1 haplotypes were identified, which included 11 novel ones. The phylogenetic tree of the AMA-1 haplotypes revealed multiple clades of AMA-1, each of which contained parasites of multiple geographical origins, consistent with the F(st) indices indicating genetic homogeneity or gene flow among geographically distinct populations of P. falciparum in Thailand's borders with Myanmar, Laos and Cambodia. In summary, the study revealed novel haplotypes and population structure needed for the further advancement of AMA-1-based malaria vaccines in the GMS.
