A general SNP-based molecular barcode for Plasmodium falciparum identification and tracking

Area of Science:

• Genetics
• Parasitology
• Molecular Biology

Background:

• Single nucleotide polymorphism (SNP) genotyping enables development of practical, rapid, and inexpensive assays for Plasmodium falciparum parasite identification.
• Such assays are crucial for distinguishing parasite recrudescence from re-infection in drug trials and for monitoring parasite populations.

Purpose of the Study:

• To develop a robust genotyping assay for unique Plasmodium falciparum parasite identification using single nucleotide polymorphism (SNP) markers.
• To create a molecular barcode for tracking parasite isolates in laboratory and clinical settings.

Main Methods:

• Identification of 24 single nucleotide polymorphism (SNP) markers with high minor allele frequency (>35%) through whole genome sequencing.
• Construction of robust TaqMan genotyping assays for the identified SNPs.
• Estimation of minor allele frequency (MAF) using Affymetrix array-based genotyping of a global parasite collection.

Main Results:

• A panel of 24 SNP markers generates a unique allele signature, with no two independently originated parasites sharing the same signature.
• TaqMan genotyping assays demonstrate >99% success rate on various sample types (cultured parasites, whole blood, filter paper).
• The assay requires <5 ng of parasite DNA and performs comparably to standard MSP-1 and MSP-2 typing methods.

Conclusions:

• The developed SNP panel provides a facile, field-deployable genotyping tool for unambiguous Plasmodium falciparum parasite identification and tracking.
• The assay requires no special skills, uses standard laboratory equipment, and is cost-effective.
• This tool is valuable for both patient samples and laboratory-based parasite monitoring.