Genetic variability revealed in malaria genomes newly sequenced by
two multi-national research teams points to new challenges in efforts to
eradicate the parasite, but also offers a clearer and more detailed
picture of its genetic composition, providing an initial roadmap in the
development of pharmaceuticals and vaccines to combat malaria.
The
research appears in two studies published in the latest issue of the
journal Nature Genetics. They focus on Plasmodium vivax (P. vivax), a
species of malaria that afflicts humans and the most prevalent human
malaria parasite outside Africa, and Plasmodium cynomolgi(P. cynomolgi),
a close relative that infects Asian Old World monkeys.
"The bad
news is there is significantly more genetic variation inP. vivax than
we'd thought, which could make it quite adept at evading whatever
arsenal of drugs and vaccines we throw at it," said Professor Jane
Carlton, senior author on both studies and part of New York University's
Center for Genomics and Systems Biology. "However, now that we have a
better understanding of the challenges we face, we can move forward with
a deeper analysis of its genomic variation in pursuing more effective
remedies."
In one study, the researchers examined P. vivax strains
from different geographic locations in West Africa, South America, and
Asia, providing the researchers with the first genome-wide perspective
of global variability within this species. Their analysis showed that P.
vivax has twice as much genetic diversity as the world-wide Plasmodium
falciparum (P. falciparum) strains, revealing an unexpected ability to
evolve and, therefore, presenting new challenges in the search for
treatments.
The second study, performed jointly with Professor
Kazuyuki Tanabe at Osaka University, Japan, sequenced three genomes of
P. cynomolgi. The researchers compared its genetic make-up to P. vivax
and to Plasmodium knowlesi (P. knowlesi), a previously sequenced malaria
parasite that affects both monkeys and humans in parts of Southeast
Asia.
Their work marked the first time P. cynomolgi genomes have
been sequenced, allowing researchers to identify genetic diversity in
this parasite. Its similarity to P. vivax means that their results will
also benefit future efforts to understand and fight against forms of
malaria that afflict humans.
"We have generated a genetic map of
P. cynomolgi, the sister species to P. vivax, so we can now push forward
in creating a robust model system to study P. vivax," explained Tanabe.
"This is important because we can't grow P. vivax in the lab, and
researchers desperately need a model system to circumvent this."
Much
of the work occurred under a seven-year grant from the National
Institute of Allergy and Infectious Diseases (NIAID), part of the
National Institutes of Health. The funding has established 10
International Centers of Excellence for Malaria Research (ICEMR).
Carlton is heading an ICEMR based in India, where malaria -- and P.
vivax in particular -- is a significant public health burden. A
particular aim of this Center of Excellence is to support and help train
scientists in India who can then work to combat infectious diseases,
such as malaria, where they are most prominent. The P. vivaxsequencing
was funded by NIAID as part of the NIAID funded Genomic Sequencing
Center for Infectious Diseases at the Broad Institute under Contract No.
HHSN272200900018C. The Burroughs Wellcome Fund was instrumental in
providing pilot funds for the P. cynomolgi sequencing.
Researchers
at the following institutions were also part of theP. vivax sequencing:
The Broad Institute, the National Institute of Malaria Research in
India, Arizona State University, and the Centers for Disease Control and
Prevention.
Researchers at the following institutions were also
part of the work on P. cynomolgi: Osaka University, Dokkyo Medical
University, Japan's Corporation for Production and Research of
Laboratory Primates, Nagasaki University, Juntendo University's School
of Medicine, the University of Tokyo, the National Institute of
Biomedical Innovation, the Centers for Disease Control and Prevention,
and Arizona State University.
Source: Science Daily, the daily star, bangladesh
