It can help prevent spread of drug-resistant malaria from one region to another
An international team of researchers led by the London School of Hygiene and Tropical Medicine, United Kingdom, has identified segments in the DNA of malaria-causing parasite that point to its region of origin.
The researchers studied Plasmodium falciparum DNA and constructed a barcode of 23 DNA segments that can be used to monitor and contain the import of new malaria cases through international travel. The barcode could also help public health agencies prevent the spread of drug-resistant malaria from one region to another.
Studying the DNA of 711 parasite samples from 14 countries across five regions—West Africa, East Africa, Oceania, South East Asia and South America—the researchers found greater differences between DNA of parasites originating from the five regions than those originating from countries of the same region.
Instead of going for the obvious choice of DNA packed in the nucleus of a parasite, the researchers turned to DNA found in its cell organelles, mitochondrion and apicoplast. “Studies tend to focus on nuclear [DNA], which undergoes a lot of changes,” says Taane G Clark, researcher and lead author of the work. “But we focused on mitochondrial and apicoplast DNA.” DNA present in these organelles does not change much from one parasite generation to another, and is, therefore, more reliable in tracing the origins.
Clark and co-workers are now aiming to get parasite DNA samples from the Indian subcontinent and Central America, which they left out in the study due to non-availability of DNA sequencing data. Clark told Down to Earth, “We are interested in other species of the parasite, too and are trying to use a similar approach to find a barcode specific to Plasmodium vivax.”
The research was published in the journal Nature Communications on June 13.
Daniel Neafsey, who leads the Malaria Genome Sequencing and Analysis Group at Broad Institute in the United States, says the value of this work lies in that it used pre-existing whole genome sequence data to show that a fairly small number of short DNA segments can be used to confidently predict geographic origin of the parasite.
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