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Biological Chemistry

Gene-Editing Technique Raised Ethics Questions

Biotechnology: As the fast and accurate CRISPR/Cas9 method gained popularity, it also ignited concerns about the creation of designer babies

by Sarah Everts
December 21, 2015 | A version of this story appeared in Volume 93, Issue 49

Credit: McGovern Institute for Brain Research/MIT
The Cas9 enzyme docks onto target DNA to begin editing.
An image of Cas9 docking onto DNA.
Credit: McGovern Institute for Brain Research/MIT
The Cas9 enzyme docks onto target DNA to begin editing.

Excitement about the gene-editing method called CRISPR/Cas9 reached epic proportions this year as scientists reported a potpourri of promising applications for the genomic cut-and-paste technology. For instance, researchers demonstrated they could recode pig DNA so the animals might produce organs for human transplants, and they engineered mosquitoes so that the insects kill the malaria pathogen.

The buzz wasn’t all positive though. In April, Chinese scientists reported modifying the DNA of human embryos to prevent a rare blood disorder. Although these embryos were nonviable—they couldn’t result in a pregnancy—a public outcry arose that the scientists had taken an alarming step toward the creation of designer babies.

Although scientists have been tweaking DNA sequences since the 1970s, about four years ago researchers discovered how to dramatically improve the speed, ease, specificity and accuracy of gene editing compared with previous techniques. The new CRISPR/Cas9 technology was developed from cellular machinery that bacteria use to excise foreign viral DNA.

Concern over the new technique led to a summit in early December attended by scientific pioneers of the field, bioethicists, patient advocates, regulators, and entrepreneurs to discuss potential guidelines for gene-editing regulations worldwide.

After grappling with the issue for three days, the organizers of the International Summit on Human Gene Editing—a group of 12 scientists and bioethicists—issued a statement that urged caution but that did not call for a ban on using the gene-editing technology to alter the DNA of human eggs, sperm, and early-stage embryos. Instead, it suggested that scientists should not proceed in using gene-editing techniques to remove disease-associated DNA or to enhance human capabilities in clinical settings until safety and efficacy concerns have been thoroughly allayed, until there is broad social consensus to do this sort of editing, and until the research has followed appropriate regulatory oversight. “At present, these criteria have not been met for any proposed clinical use,” summit organizers noted.

They also emphasized that edited human embryos or germline cells produced during basic research “should not be used to establish a pregnancy.”


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