GoKawiilA four-celled human embryo. Credit: Juan Gaertner/Science Photo Library
Researchers say that they have used a precise genome-editing technique called base editing to alter the genome of human embryos. The announcement has prompted excitement and caution from scientists and bioethicists. Many say that the work is an impressive step towards clinicians being able to fix disease-causing mutations in embryos. But others worry that the technology could be used to try to create embryos with traits such as superior intelligence.
Dieter Egli, a developmental cell biologist at Columbia University in New York City, and his colleagues posted their results on the bioRxiv preprint server on 1 June1. The study, which was first reported by The New York Times, has not yet been peer reviewed
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Previous studies had suggested that the use of a standard but less precise form of gene editing in embryos can cause the loss of the edited chromosomes — an effect that made the technology unusable in embryonic cells. The new work is “a conceptual shift” that really has the potential to move the field forwards, says Emre Seli, a fertility specialist at Yale University in New Haven, Connecticut. “This will go down in history in a positive way — less reckless, more careful and ethical than previous attempts,” says Greg Neely, a genomics researcher at the University of Sydney in Australia.
But some researchers expressed concern about the implications of the work. Hank Greely, a biomedical ethicist at Stanford University in California, worries that affluent individuals might be inspired by the study as a jumping-off point to edit embryos.
“You could set up an [in vitro fertilization] lab and a genetic-testing lab for probably a handful of millions of dollars and start doing this,” says Greely. “And one result might be really sick kids.”
Egli responds that the data in the preprint show that such an effort would be premature because of the risks of applying base editing to embryos.
Gene-edited babies
Members of the genome-editing field still remember the actions of Chinese scientist He Jiankui, who used an earlier genome-editing technique called CRISPR–Cas9 to edit the DNA of human embryos in 2018. He then implanted those embryos into two women who went on to give birth to babies. His work provoked widespread outrage among scientists, who said that the technology was too risky to be used in people. He ultimately spent three years in prison for illegal medical practice in China. In an interview published in January, He told The New York Times that he was “very proud” of his work.
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