Korean J Parasitol.  2019 Aug;57(4):445-450. 10.3347/kjp.2019.57.4.445.

Low Levels of Polymorphisms and Negative Selection in Plasmodum knowlesi Merozoite Surface Protein 8 in Malaysian Isolates

• Ahmed MA
• Kang HJ
• Quan FS

• KMID: 2459485
• DOI: http://doi.org/10.3347/kjp.2019.57.4.445

Abstract

Human infections due to the monkey malaria parasite Plasmodium knowlesi is increasingly being reported from most Southeast Asian countries specifically Malaysia. The parasite causes severe and fatal malaria thus there is a need for urgent measures for its control. In this study, the level of polymorphisms, haplotypes and natural selection of full-length pkmsp8 in 37 clinical samples from Malaysian Borneo along with 6 lab-adapted strains were investigated. Low levels of polymorphism were observed across the full-length gene, the double epidermal growth factor (EGF) domains were mostly conserved, and non-synonymous substitutions were absent. Evidence of strong negative selection pressure in the non-EGF regions were found indicating functional constrains acting at different domains. Phylogenetic haplotype network analysis identified shared haplotypes and indicated geographical clustering of samples originating from Peninsular Malaysia and Malaysian Borneo. This is the first study to genetically characterize the full-length msp8 gene from clinical isolates of P. knowlesi from Malaysia; however, further functional characterization would be useful for future rational vaccine design.

Keyword

Plasmodium knowlesi; pkmsp8; merozoite surface protein 8; genetic diversity; natural selection; haplotype; polymorphism; Malaysia

MeSH Terms

Asian Continental Ancestry Group
Borneo
Epidermal Growth Factor
Genetic Variation
Haplorhini
Haplotypes
Humans
Malaria
Malaysia
Merozoites*
Parasites
Plasmodium knowlesi
Selection, Genetic
Epidermal Growth Factor