The Malaria Atlas Project estimates 2.5 billion people worldwide are at risk for P. vivax malaria.
P. vivax does not grow well in the laboratory, so to try to understand how the parasite lives and operates, the researchers gathered samples from malaria patients and focused on its genome.
They found a duplication of the Duffy binding protein in half of 189 P. vivax infection samples taken in Madagascar. Other researchers' prior efforts to sequence the P. vivax genome missed the duplication but all indications are it's a recent change, Serre said.
"The way we date duplications is to compare differences between the two parts: the more different they are, the older they are," he explained. "They accumulate mutations. The two parts of this duplication have, among 8,000 base pairs, only one difference."
Often a second copy of a gene enables an organism to outmaneuver a defense, Serre continued. "Instead of making a supergene, a duplication is simpler for nature."
The researchers suspect the mutation is spreading from Madagascar through travelers. They found the duplication in less than 10 percent of samples from Cambodia and Sudan.
The new components found on the P. vivax genome are two proteins that closely resemble binding proteins used by related malaria parasites to enter immature and mature red blood cells. Both were present in samples from Cambodia, Brazil, Mauritania and North Korea.
The new proteins were absent in a
|Contact: Kevin Mayhood|
Case Western Reserve University