GoKawiilA four-celled human embryo. Credit: Juan Gaertner/Science Photo Library
Researchers say they have used a precise genome-editing technique called base editing to alter the genome of human embryos for the first time. The announcement has prompted excitement and caution among scientists and bioethicists. Many say the work is an impressive step towards scientists being able to fix disease-causing mutations in embryos. But others worry the technology could be deployed 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 site 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 The study, which was first reported by The New York Times, has not yet been peer reviewed.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 embryos. The new work is “a conceptual shift ... that really has the potential to move the field forward,” says Emre Seli, an obstetrician and gynaecologist 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 base-edit their 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. ... And one result might be really sick kids,” says Greely.
Egli responds that data in his preprint show such an effort would be premature because of the risks of applying base-editing to embryos.
Gene-edited babies
The field of genome editing still lives with the memory of Chinese scientist He Jiankui, who in 2018 used a first-generation genome editing technique called CRISPR-Cas9 to edit the DNA of human embryos. 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 the technology was too risky to be used in people, and He ultimately spent three years in prison for illegal medical practice in China. He told The New York Times in January that he was “very proud” of his work.
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