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Why scientists are calling for caution on a powerful new gene-editing technology

A human embryo.
A human embryo.

Earlier this week, hundreds of scientists, bioethicists, and health regulators gathered in Washington, DC, to talk about the powerful new gene-editing system that recently exploded onto the scientific scene.

CRISPR-cas9 — or CRISPR, as it's known — allows researchers to edit, cut out, and replace genes in any animal more quickly and efficiently than anything that's come before. The technology has the potential to allow us to better understand our biology and how certain diseases work, and perhaps even delete horrible diseases right out of the human genome. Even more fantastically, it's at least theoretically possible to use CRISPR to hack the human race — to design humans to look or speak a certain way, or develop resistances to chronic or infectious diseases. (You can read about how CRISPR works here.)

But just because we have the power to do something doesn't mean we should. And talking about what scientists should do with CRISPR was the point of the international summit at the National Academy of Sciences.

Scientists: It's okay to use CRISPR in the lab — but not to edit the human race

After the summit, the academy came out with a consensus statement on how to proceed with CRISPR research. The document reflects the excitement and wonder of this new technology, but it also calls for a slowdown on research involving hacking the human genome in ways that could be passed down to future generations.

Specifically, the statement drew the line at clinical research that involves editing the human "germline" — or the DNA of sperm, eggs, and embryos that could be inherited by future generations. Such editing could involve, for instance, taking an embryo, altering DNA related to a genetic disease, then using that embryo to establish pregnancy and seeing whether that disease is indeed deleted from that person and her children.

Though the academy acknowledged that such research had the potential to eradicate terrible genetic diseases or "enhanc[e] human capabilities," they also said the science is just too new to do any of that safely or successfully.

There are a number of risks involved, many of them still unknown, and great potential for "inaccurate" editing — not to mention all the moral and ethical problems that come with applying CRISPR to the germline. For example, the academy said, future generations won't be able to opt out of inheriting edited DNA, genetic changes might be difficult to undo, and there's also "the possibility that permanent genetic ‘enhancements’ to subsets of the population could exacerbate social inequities or be used coercively."

So far, research on human embryos hasn't gone that far. When researchers in China tried to apply the CRISPR-cas9 system to 86 embryos, only a small fraction of those that survived were successfully modified with the new genetic material.

Still, the group at the National Academy of Sciences didn't completely rule out the possibility of further attempts. In fact, they said that "the clinical use of germline editing should be revisited on a regular basis."

They also argued that it's okay to use germline cells or early human embryos in basic and preclinical laboratory research — as long as they're not then used "to establish a pregnancy." (This goes further than the line the National Institutes of Health's director, Francis Collins, drew on the publication of the China experiment last spring. He said the NIH would not fund genomic editing involving human embryos, even if the embryos weren't not used to create a pregnancy.)

When it comes to clinical research on somatic cells (which are unlike germline cells in that they aren't passed down to future generations), the National Academy group said that it's okay to proceed here with caution. Editing non-heritable genes could involve snipping sickle cell anemia out of a person's blood cells or enhancing a cancer patient's immune cells to fight off the disease. The scientists rationalized this by noting that the treatment would only affect the individual who signs up for it — not future generations — and there are well-established regulatory frameworks in place for other types of gene therapy that can be applied here.

No designer babies anytime soon


(Thorsten Schmitt/Shutterstock)

Even if researchers don't follow these guidelines, the consensus at the conference seemed to be that the excitement right now is mostly in understanding and refining this new gene editing system and doing pre-human work in the lab to suss out its potential.

While much of the public's fascination with CRISPR seems to relate to its potential to create "designer babies," the researchers all seemed to agree that there's much to learn before that's even possible.

"The technology is clearly moving very quickly," Jennifer Doudna, one of the CRISPR inventors, said. "But I think the reality is we don't understand enough yet about the human genome, how genes interact, which genes give rise to certain traits, in most cases, to enable editing for enhancement today." Still, she added: "That’ll change over time."