For the past 30 years, researchers around the world have been trying to engineer the DNA of mosquitoes in a way that would make them resistant to the parasite that causes malaria. The major question is how to ensure these mutant “mozzies” pass their genes to all of their offspring – not just half as would normally be the case?
In a new study, published on November 23, 2015, a group of scientists have used a controversial method called “gene drive” to achieve just that, bringing us closer to eradicating the disease for good.
“This work suggests that we’re a hop, skip and jump away from actual gene-drive candidates for eventual release,” said Kevin Esvelt, an evolutionary engineer at Harvard University in Cambridge, Massachusetts, who studies gene drive in yeast and nematodes.
This was achieved by employing the gene-editing system CRISPR-Cas9 to introduce two genes into the mosquito genome that were demonstrated to confer resistance to the malaria parasite in previous studies. The resulting mosquitoes passed on the modified genes to more than 99% of their offspring.
“It’s a very significant development,” said Kenneth Oye, a political scientist who studies emerging technologies at the Massachusetts Institute of Technology in Cambridge. “Things are moving rapidly in this field.” So rapidly, in fact, that technological advances are outpacing the regulatory and policy discussions surrounding the use of gene drives to engineer wild populations.
The main concern with research of this type and magnitude is the potential for altering entire ecosystems. To ensure nothing inadvertent happens the researchers are experimenting on non-native mosquito species that wouldn’t be able to mate and spread the drive even if they escaped the lab.
Anthony James, a molecular biologist at the University of California, Irvine, and an author of the paper predicts that it will take his team less than a year to prepare mosquitoes that would be suitable for field tests, but he is in no rush to release them. “It’s not going to go anywhere until the social science advances to the point where we can handle it,” he says. “We’re not about to do anything foolish.”