Members of the International Union for Conservation of Nature (IUCN), which is holding its World Conservation Congress in Honolulu through Saturday, recently approved a motion that would prohibit the organization from supporting or endorsing any research or field trials on the use of gene drives until a comprehensive assessment of the technology’s effects has been undertaken.
The motion is nonbinding and does not dictate the regulations that individual countries may choose to establish for themselves. But it does reflect a growing concern among scientists and environmentalists about the technology’s potential power to irrevocably alter species and reshape ecosystems.
A gene drive is a stretch of DNA that gets passed on to offspring more frequently than regular genes. In most sexually reproducing organisms, offspring have a 50 percent chance of inheriting a given trait from one of their parents. Gene drives increase the odds.
To be clear, gene drives are a naturally occurring phenomenon – they are found in all kinds of species in nature. But it was not until recently, with the advent of new genetic engineering tools, that scientists realized they could be harnessed by humans.
Genetic editing tools such as CRISPR allow scientists to make precise cuts and splices in an organism’s DNA, allowing them to physically alter genes and change the traits that they code for. Recently, researchers also realized that such tools could also be used to attach gene drives to DNA sequences, greatly increasing the likelihood that these genes would be passed on.
Scientists have already begun to brainstorm ways this technology could be used for conservation purposes. In Hawaii, for instance, some scientists have suggested it could be used to save a group of endangered endemic birds known as honeycreepers. One of the many threats facing these birds is avian malaria. Scientists have suggested that gene drive technology could be used to render mosquitoes on the islands incapable of transmitting the disease, by tricking the mosquitoes’ immune systems into attacking the parasite that causes malaria.
It’s a different concept from the genetically modified mosquitoes developed by biotech company Oxitec, currently being used to combat Zika in Brazil. The Oxitec mosquitoes are engineered with a “self-destruct” gene that causes their offspring to die before reaching adulthood. While these mosquitoes have been genetically modified, there is no gene drive involved.
Still, gene drive technology could theoretically be used to kill off species in a similar way. Some scientists have suggested, for instance, that gene drives could be used to eradicate invasive populations of rats and mice from islands by engineering the rodents to only produce male offspring.
But while there’s clear potential for the technology to do good, many experts have expressed concern about the potential changes it could cause in the natural world. Gene drives in their most aggressive forms have the potential to spread irreversibly throughout entire species, and it is not clear how this effect could affect the environment.
In an open letter aimed at members of the IUCN, worried environmentalists expressed their concern about the technology’s implications. “Given the obvious dangers of irretrievably releasing genocidal genes into the natural world, and the moral implications of taking such action, we call for a halt to all proposals for the use of gene drive technologies, but especially in conservation,” they wrote.
However, it’s important to note that gene drive technology can take several different forms, and some are safer than others, said Floyd Reed, an associate professor of biology at the University of Hawaii. Reed’s lab is involved in gene drive research on fruit flies, with plans to begin moving forward with mosquitoes next.
Although reversible systems are still not completely understood, a moratorium on research or even field trials for this type of technology may not be necessary, he said, so long as they are subject to rigorous regulation and public consultation.