The Bill and Melinda Gates Foundation plans to double the sum it is spending to create a mosquito-killing technology that relies on CRISPR gene editing.

The technique, called a gene drive, is a way to spread traits through wild populations of animals, but its ability to alter nature is drawing opposition from some environmental groups.

The Gates-funded project, called Target Malaria, is based at Imperial College, London, and has been seeking to add instructions to the DNA of malaria mosquitoes that would cause them to become sterile. If released in the wild, a gene drive could push these species to extinction.

Spokesman Bryan Callahan says the Gates Foundation will give Target Malaria an additional $35 million, bringing Gates’s total investment to $75 million. That is the largest sum ever spent on gene-drive technology.

Scientists at Imperial and elsewhere first succeeded in installing gene drives in mosquitoes last year—in lab research—setting off a global debate over whether the technology is safe enough to use.

Bill Gates

The new money will help Target Malaria “explore the potential development of other constructs, as well as to start mapping out next steps for biosafety, bioethics, community engagement, and regulatory guidance,” says Callahan. “It’s basically a lot of groundwork.” The Gates Foundation views the technology as a “long shot” that won’t necessarily work but, if it does, could effectively end malaria.

The foundation previously said it plans to have a gene-drive approved for field use by 2029 somewhere in Africa. But Gates, the founder of Microsoft, offered more enthusiastic prognostications in comments made this summer, saying the technology might be ready in just two years.

A gene drive works by spreading genetic instructions as animals mate. For instance, if a drive causes only male animals to be born, a population would quickly crash as it runs out of females. It may also be possible to change mosquitoes so they are unable to transmit malaria, which is a significant cause of death in children in sub-Saharan Africa.

In a report earlier this year, the National Academies of Sciences, Engineering, and Medicine in Washington, D.C., said gene drives were not yet ready for environmental release, but laid out steps that should be taken to test them safely, recommendations the Gates Foundation says it will follow.

Splitting conservationists

Genetic techniques for “bio-control” have also caught the eye of conservationists as a way to kill off invasive species, including mosquitoes, rats, toads, or fish that take over ecosystems and can drive local species to extinction.

Over the weekend, during the world congress of the International Union of Conservation of Nature in Hawaii, the nonprofit Island Conservation announced it had started a project to genetically engineer mice so they only produce male offspring.

The group believes gene drives will be a way to wipe invasive rodents off islands and archipelagos, where they prey on birds and lizards. Other researchers hope to eradicate mosquitoes from Hawaii in order to save the island chain’s remaining native birds, which are succumbing to the avian form of malaria.

Other conservation groups, however, circulated a petition at the Hawaii meeting calling for a moratorium on the idea. They worry that promoting drives as conservation tools could pave the way for commercial use of gene drives, say to manage agricultural pests. “Genetic extinction technologies are a false and dangerous solution to the problem of biodiversity loss,” Erich Pica, president of the Friends of the Earth, said in a statement signed by anti-GMO campaigners that called the technology reckless.

Heath Packard, a spokesman for Island Conservation, said his group is willing to consider the technology because 90 percent of the world’s island chains are infested with rodents. It has previously eradicated rats from some islands, including in the Galapagos, using poisoned bait. But efforts to poison rats are expensive, hard to pull off on larger islands, and can create risks for other animals.

Packard says the mouse project is being carried out with Texas A&M, North Carolina State University, and the U.S. Department of Agriculture. While mice aren’t as big a problem as rats, they have infested the Midway atoll in the Pacific, and videos posted online of them eating albatross chicks alive have galvanized bird lovers. He says the nonprofit hopes to have a proposal in front of regulators for a field trial within four years.

The debate over drives could rival that over GMOs in its intensity and, ultimately, its global consequences. That is because, like GMO plants, the gene drives would affect our shared environment.

But conservationists and public health campaigners see a one-of-a-kind chance to solve big problems and aren’t likely to stop their efforts to perfect the technology in the lab. “We need some transformative end-game technologies, and this is one of them,” says Callahan.