Research on a genetic engineering technique that, for the first time, could enable scientists to quickly modify entire populations of organisms in the wild should continue in the laboratory — and potentially under restrictive conditions in the field — an expert panel said Wednesday.
This “gene drive” technology, in its current form, is only two years old, but some are already calling for its use against mosquitoes that carry Zika virus or malaria. The National Academies of Sciences, Engineering, and Medicine panel reins in this enthusiasm.
“There is insufficient evidence available at this time to support the release of gene-drive modified organisms into the environment,” it writes. However, it adds, “highly-controlled field trials” should proceed.
Gene drives enable genetic modifications to a single organism to spread rapidly through the entire population by ensuring that targeted genes are passed on to nearly all offspring. Scientists could release swarms of mosquitoes that produce sterile offspring, reducing the number of bugs that can transmit malaria or Zika virus. Or, they could engineer mice not to transmit Lyme disease to ticks – an idea aired at a community meeting Monday on Nantucket.
Some scientists urge caution even in conducting controlled experiments, noting how powerful even a single organism might be.
“There is a nontrivial chance that [the genes] will spread from a single organism released into a wild population into most or all members of the local population — and very possibly into every population of the target species around the globe,” said Kevin Esvelt, an MIT Media Lab professor who has studied gene drives in yeast. “This makes field trials of [current gene] drives unwise.”
The technology itself is spreading so quickly through the scientific community that the government is struggling to catch up — it’s unclear who, if anyone, would have the authority to regulate this technology or prevent scientists from releasing modified organisms.
“There is nothing in our regulatory system that could possibly take on this challenge given the glacial pace of regulating chemicals and of the voluntary regulations in certain areas of food biotechnology,” said Sheldon Krimsky, a Tufts University professor of urban and environmental policy and planning.
The report notes that gene drives could have unintended consequences — mosquitoes modified not to transmit the dengue virus might become better at transmitting a different virus, for example, while sterilization and removal of mosquitoes may upset the balance of the ecosystem. So, the report calls for intense consideration of environmental, social, and economic issues.
It recommends “phased testing” — starting in a lab, moving up to field-based research, and eventually releasing organisms into the wild.
To prevent the genes from migrating to unintended organisms, these experiments must be carefully isolated from the surrounding environment. The report recommends that field trials could take place in geographically-isolated areas, such as islands, or occur far away from environments into which the gene drive might spread.
Currently, lab work with gene drives is done with extensive security precautions — one experiment was conducted behind five locked doors, and the engineered flies were kept inside three nested containers.
Researchers lauded the report as a good start to the conversation about a territory lacking clear regulation, but some say that the panel should have explicitly instructed researchers to engage members of the public before doing their research.
This is critical because gene drives, in their current form, are all about unilaterally and rapidly changing environments shared by many people, Esvelt said.
“We should at the very least have the courtesy to inform people what is being planned — and let them voice their opinions — before we begin,” he said.
The question of where eventual field research might occur also comes up in the report. The authors note that such research “is most likely to occur” in “low- and middle-income countries,” and thus it is especially important to build long-term relationships with scientists in those countries.
“Starting the work in low-income countries is especially problematic,” said Jaydee Hanson, a policy director at the International Center for Technology Assessment. He pointed out that the United States did not ratify international environmental treaties, such as the Convention on Biological Diversity, and other countries may be skeptical of US researchers conducting field trials in their backyards.
Sharon Begley contributed reporting.
