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  • ‘Malarial barcode’ find spurs sequencing effort in India

Image credit: Wellcome Library, London

Speed read

  • ‘Whole genome sequences’ are unavailable for Indian parasite strains

  • A study shows that such data could be a powerful tool for tackling the disease

  • This has prompted a move to sequence the whole genomes of local strains

[THIRUVANANTHAPURAM, INDIA] The discovery of a new ‘genetic barcode’ that could help track drug-resistant strains of the malaria parasite has spurred Indian scientists to assist prevention efforts by collecting the entire genome of local parasite varieties.

‘Whole genome sequencing’ is a relatively new technique that unravels the genetic code of the assorted DNA sequences in different parts of cells, for example in mitochondria as well as the nucleus.
Genetic markers found with this technique could be used to monitor the spread of strains of malaria, including drug-resistant varieties, and help develop disease-control strategies tailored to specific locations, researchers say.

But because the technique is new, there are certain regions where scientists have yet to collect data on local strains of Plasmodium falciparum, a malaria parasite, according to Cally Roper, a malaria genetics researcher at the London School of Hygiene & Tropical Medicine, United Kingdom.

These areas include much of the Indian subcontinent plus Nigeria and the Democratic Republic of Congo, she says.

Aparup Das, a researcher at the National Institute of Malaria Research, in New Delhi, India, says India faces an additional hurdle in collecting whole genome data because national law prohibits foreign scientists from working on the blood samples they need from infected Indian citizens unless they collaborate with local scientists.

But a study authored by Roper and published in Nature Communications on 13 June shows that DNA from a little-studied component in the cells of malaria parasites — an apicoplast — can act like a ‘genetic barcode’ and be used to monitor the spread of various strains. 

Das, who was not involved in the study, tells SciDev.Net that he and Roper have now agreed to collaborate on the whole genome sequencing of Indian samples.

“Our work together will add Indian samples to the available data and fill the obvious gap,” he says.

The study’s authors say genetic markers that tracked the spread of polio were an invaluable tool in tackling that disease and have “enormous potential” in the fight against malaria too.

Das explains that, once equipped with the barcodes that demarcate the various strains of malaria in India, it should be possible for scientists to track when drug-resistant strains spread to new areas. This could help develop disease-prevention strategies tailored to specific areas.

“Considering the diversity of malaria parasites, even in a single country, any global intervention — either by drugs or vaccines — will not work,” says Das. “There is a need for population-specific drugs or vaccines.”

The authors say that they will look to expand the technique to other species of malaria causing parasites, including Plasmodium vivax.

Link to the Nature Communications paper


References

Nature Communications doi: 10.1038/ncomms5052 (2014)
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