Naoko SakihamaMasatsugu KimuraKenji HirayamaTozo KandaKesara Na-BangchangSomchai JongwutiwesDavid ConwayKazuyuki TanabeOsaka Institute of TechnologyOsaka City University Medical SchoolSaitma Medical University Faculty of MedicineJapanese Association for Mental HealthMahidol UniversityChulalongkorn UniversityLondon School of Hygiene & Tropical Medicine2018-09-072018-09-071999-04-01Gene. Vol.230, No.1 (1999), 47-54037811192-s2.0-0033119186https://repository.li.mahidol.ac.th/handle/20.500.14594/25345The C-terminal, cysteine-rich 19 kDa domain of merozoite surface protein-1 (MSP-1) of Plasmodium falciparum is a target of the host's humoral immunity and thus a malaria vaccine candidate. Although variation in the 19 kDa domain is limited among parasite isolates, tertiary structure-dependent intramolecular associations between the 19 kDa domain and other parts of MSP- 1 are suggested to be involved in immune evasion by allowing competitive binding of protective and non-protective antibodies directed to their epitopes, which are conformationally in close proximity but separated at the primary structure. Since allelic recombination can account for the major variability of the Msp-1 gene, we examined whether linkage disequilibrium occurs between polymorphic loci in the 5'- and the 3'-region, the latter encoding the 19 kDa domain. From 184 Thai field isolates, we selected 69 isolates with a single allelic type in six variable blocks of Msp-1 as determined by PCR-based allelic typing. All the isolates showed no evidence of recombination in blocks 6 to 16, whereas recombination was apparent in blocks 2 to 6. Sequencing of the 3'-region revealed two potential recombination sites in block 17. Strong linkage disequilibrium was seen between polymorphic loci in the 5'- and 3'-regions. The strength of this disequilibrium did not correlate with distance between loci. We discuss the possible role of epistatic selection on particular association types (haplotypes) of Msp-1.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyArticleSCOPUS10.1016/S0378-1119(99)00069-4