Science – The ethical and practical debates over using the DNA-editing method CRISPR to alter human embryos just got less hypothetical. A week after the news leaked out, a U.S.-based team has published the first rigorous demonstration that CRISPR can efficiently repair a gene defect in human embryos—one that would cause a potentially deadly heart condition—without introducing new mutations elsewhere. Although none of the labmade embryos were transferred into women, the research team, led by embryologist Shoukhrat Mitalipov of Oregon Health and Science University (OHSU) in Portland, says the success paves the way for using the technique in the clinic to prevent the transmission of genetic disease.
Because their approach appears to avoid the problems of patchy and imprecise editing seen in previous CRISPR tests on human embryos, the researchers claim it’s a viable strategy for rescuing mutated embryos that would otherwise be screened out of in vitro fertilization (IVF) procedures. But evidence of the technique’s long-term safety is still lacking, and many researchers and ethicists have argued that germline editing—making permanent, heritable changes to the genome that could correct genetic disease, but also theoretically introduce other designer traits—should for now be limited to research exploring basic biology.
“I’m uncomfortable, honestly, with the sort of stated purpose of this study,” says Jennifer Doudna, a molecular biologist at the University of California, Berkeley, who is among the pioneers of the CRISPR method. “It’s not about research, I don’t think. It’s about how we get to a clinical application of this technology.”
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