While politicians and climate scientists converged on Paris on Monday to hammer out a global warming accord, an international cadre of geneticists, biologists, ethicists and scientific policymakers opened a three-day conference in Washington to debate the way forward on a far more subtle man-made challenge: genome editing.
The question before the U.S. National Academies of Science, Engineering and Medicine, Britain’s Royal Society and the Chinese Academy of Sciences: Now that new techniques have made the editing of an organism’s germ line a relative snap, should we use the new tools, and how?
Hanging in the balance are genome-editing practices that could have broad agricultural and environmental applications. But the scientific and ethical issues raised by those applications are eclipsed by concerns over the prospective use of genome-editing techniques on humans.
The editing of a human individual’s “germ line” would introduce changes that not only change his or her DNA for life: that changed genetic architecture would be passed on to future generations. Essentially, new and widely available techniques for genome editing would allow scientists to seize the reins of evolution and bypass the glacial process by which natural selection has evolved a range of human traits, including a propensity for certain diseases.
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The use of these techniques could permanently expunge a devastating genetic disease from a family’s tree. But many scientists worry that it could saddle future generations with new and unforeseen genetic changes — including harmful mutations — that might not be reversed or eradicated so easily.
The unfathomable possibility of such “off-target effects,” as they are called, haunts scientists who would otherwise focus on the remarkable curative possibilities.
On Monday, two scientists — Harvard University geneticist George Church and Jennifer Doudna, a molecular and cell biologist at the University of California, Berkeley — previewed that debate in the pages of the journal Nature.
Doudna renewed her clarion call against genome editing in humans — a position that all parties to the conference (though neither the Chinese nor U.S. governments) have voluntarily agreed to for now.
Church contended that regulatory mechanisms are up to the task of policing a cautious path forward on genome editing. Continuing the voluntary ban would “put a damper on the best medical research,” he added, driving human genome editing underground where, unregulated, it could run amok.
Both scientists appear to agree that a newly devised genome-editing technique called CRISPR-Cas9 has made an outright ban on its use impractical. These easy-to-use, inexpensive and effective genome-editing methodologies have “changed the landscape of biology,” wrote Doudna.