Scientists have launched a major new phase in the testing of a controversial genetically modified organism: a mosquito designed to quickly spread a genetic mutation lethal to its own species, NPR has learned.
For the first time, researchers have begun large-scale releases of the engineered insects, into a high-security laboratory in Terni, Italy.
“This will really be a breakthrough experiment,” says Ruth Mueller, an entomologist who runs the lab. “It’s a historic moment.”
The goal is to see if the mosquitoes could eventually provide a powerful new weapon to help eradicate malaria in Africa, where most cases occur.
“It’s very exciting,” Mueller says.
NPR was the only news organization allowed into the lab to witness the moment the releases began in early February.
The lab was specially built to evaluate the modified insects in as close to a natural environment as possible without the risk of releasing them into the wild, about which there are deep concerns regarding unforeseen effects on the environment.
“This is an experimental technology which could have devastating impacts,” says Dana Perls of Friends of the Earth, an environmental group that’s part of an international coalition fighting this new generation of modified organisms.
To prevent any unforeseen effects on the environment, scientists have always tried to keep genetically engineered organisms from spreading their mutations.
But in this case, researchers want the modification to spread. So they engineered mosquitoes with a “gene drive.”
A gene drive is like a “selfish gene,” Mueller says, because it doesn’t follow the normal rules of genetics. Normally, traits are passed to only half of all offspring. With the gene drive, nearly all the progeny inherit the modification.
“All the offspring. All the children — the mosquito children — have this modification,” Mueller says.
Researchers created the mosquitoes by using the powerful new gene-editing technique known as CRISPR, which Mueller likens to a “molecular scissor which can cut at a specific site in the DNA.”
The cut altered a gene known as “doublesex,” which is involved in the sexual development of the mosquitoes.
“The females become a bit more male,” Mueller says. “A kind of hermaphrodite.”
While genetically female, the transformed insects have mouths that resemble male mosquito mouths. That means they can’t bite and so can’t spread the malaria parasite. In addition, the insects’ reproductive organs are deformed, which means they can’t lay eggs.
As more and more female mosquitoes inherit two copies of the modification, more and more become sterile.
The idea is that if these modified mosquitoes are eventually shown to be safe and effective, they might someday be released in African villages plagued by malaria. The hope is that they would spread their mutation and eventually sterilize all the females. That would crash — or drastically reduce — local populations of the main species of mosquito that spreads malaria, known as Anopheles gambiae.
“Malaria is a huge problem affecting probably two-thirds of the world’s population,” says Tony Nolan, who helped develop the mosquitoes at Imperial College London. He is now at the Liverpool School of Tropical Medicine.
Malaria sickens more than 200 million people each year and kills more than 400,000, mostly young children.
Scientists think gene-drive organisms could help solve many problems, including wiping out other insect-borne diseases such as Zika and dengue. Gene-drive creatures might also save endangered ecosystems by eradicating invasive rodents. They could help feed the world by creating more efficient crops.
But critics fear that gene-drive organisms could run amok and wreak havoc if they were ever released into the wild. The insects could inadvertently have a negative effect on crops, for example, by eliminating important pollinators, they fear. The insects’ population crash could also lead to other mosquitoes coming with other diseases, critics say.
“We can’t be taking lightly this extermination technology,” Perls says. “We need to slow down. We need to hit the pause button on gene drives.”
Some activists in Africa agree.
“This is a technology where we don’t know where it’s going to end. We need to stop this right where it is,” says Nnimmo Bassey, director of the Health of Mother Earth Foundation in Nigeria. “They’re trying to use Africa as a big laboratory to test risky technologies.”
The experiment is a key step in the Target Malaria project. The project’s major funder is the Bill & Melinda Gates Foundation, which also supports NPR and this blog.
Nolan and Mueller say the project is working methodically and cautiously to assess the mosquitoes in close consultation with scientists, government officials and local residents in Africa. In addition, the gene-drive mosquitoes would affect just one of hundreds of mosquito species.
“There’s going to be concerns with any technology. But I don’t think you should throw out a technology without having done your best to understand what its potential is to be transformative for medicine. And, were it to work, this would be transformative,” Nolan says.
Other experts agree.
