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Scientists Cautiously OK the Next Genetic Revolution

ByTim De Chant, Kelsey Houston-EdwardsNOVA NextNOVA Next

Today, scientists on the cusp of the next genetic revolution released a

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report outlining their recommendations for how to safely study and implement a technology known as gene drives , which have the power to alter entire populations of wild plants and animals.

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The 218-page report published by the National Academies of Science, Engineering, and Medicine highlights the potential promise and perils of using such a powerful technology. With it, geneticists could, for example, rid the world of malaria or boost food production in tropical regions. But in the latter case, they could also unwittingly unleash extraordinarily aggressive weeds that might overwhelm temperate ecosystems.

Mosquitoes are often mentioned as a first target for gene drive technology.

The committee members reviewed the current state of the fast-changing technology and made recommendations on how gene drives should be studied and regulated. “It’s a balanced report with lots of details,” said George Church, a professor of genetics at Harvard Medical School.

“I think they’re calling for gene drives to go forward in a slow, careful manner,” said Art Caplan, a professor of bioethics at New York University School of Medicine. “It would be hard to argue that that’s a bad idea.”

Typically genes are passed to an organisms’ offspring roughly half the time. But gene drives upend this balance, forcing particular so-called selfish genes to be inherited by all offspring. The specific genes are driven through the population, hence the name “gene drive.”

Gene drives are nothing new—they occur in nature, and we’ve known about them for over a century. “But it’s only in the last few years with the advent of CRISPR-Cas9 technology and gene editing that to manufacture and create gene drives has been feasible,” said Jason Delborne, an associate professor of science, technology, and society at North Carolina State University and an member of the report committee.

CRISPR-Cas9, better known as just CRISPR, is an astonishingly simple technique for editing genomes that is upending genetics. The technology was first proven in 2012, and in just four years it has opened the door to a world of possible uses, from curing disease to exterminating pests. CRISPR enables scientists to easily insert genes to block a mosquito’s ability to transmit malaria, but without a way to ensure that these genetic modifications are inherited by the organisms’ offspring, natural selection might wipe out these traits.

But gene drives promise to dramatically dial up the power of CRISPR by allowing us to endow organisms with specific traits and then efficiently spread those traits throughout an entire population.

With CRISPR, “designing a gene drive is pretty easy—an undergrad can do it, even a high school can do it,” said Kevin Esvelt, an assistant professor of media arts and science at the MIT Media Lab who has helped spearhead the current investigations into gene drives.

But the main risk isn’t necessarily how easy it is to create a gene drive, but what might happen should a modified organism escape into the wild. Scientists are actively exploring ways to control gene drive modified organisms and their ecological impact. Labs will certainly use physical barriers, but researchers are also exploring genetic and biological controls. One suggestion is a reversal drive, a gene drive that would undo the effects of the original. Another that Esvelt has proposed is a so-called daisy drive, which works to restrict the trait to a local population.

It’s likely that experiments involving gene drives will use several of these approaches. “One of the things the report recommends is not just one sole mitigation strategy,” said Lisa Taneyhill, an associate professor of animal and avian sciences at the University of Maryland.

The report also emphasized the role of outreach on the part of scientists. “Public engagement cannot be an afterthought. Sometimes, the engagement of the public is really even more crucial to the scientific outcomes of the research as to whether a gene drive modified organism should be released,” Taneyhill said. To that end, Taneyhill and the other committee members recommended holding meetings with groups who would be impacted by gene drive modified organisms.

Community participation is the ideal, but can be difficult to implement, Caplan said. “I worry about calls for public engagement when very little effort goes into teaching scientists how to engage the public.” He cites the disconnect between scientific consensus and popular opinion about genetically modified crops as an example of failed public engagement.

There are nascent efforts toward outreach, though. Esvelt recently held a town hall-style meeting on Nantucket off the coast of Massachusetts to gauge interest in the release of white-footed mice modified to combat Lyme disease, which they carry. The island has one of the highest burdens of Lyme disease in the country.

Ultimately, urgency will dictate how quickly research into gene drives moves, Caplan said. In regions affected by disease, like Nantucket for example, there may be more appetite for experimentation. Or, he said, “if malaria were in the U.S., so would gene drives.”

Photo credit: Erik F. Brandsborg/Flickr (CC BY-SA)

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