Are scientists playing with fire? That's suddenly a big question for bioethicists, now that researchers in China have confirmed that they genetically modified human embryos for the first time ever. Rumors about the research first circulated in March, inciting a debate over its implications. Some argue that such "genome editing" holds the promise to eradicate hereditary diseases. But others fear that changing the human germ line (the genes in sperm cells and eggs) could give rise to a new era of eugenics and even pose dangerous risks to the health of future generations.
“No researcher has the moral warrant to flout the globally widespread policy agreement against altering the human germ line,” Dr. Marcy Darnovsky, executive director of the Berkeley, Calif.-based Center for Genetics and Society, said in a written statement. "Creating genetically modified human beings could easily lead to new forms of inequality, discrimination and societal conflict.”
A paper describing the findings was published online April 18 in the journal Protein & Cell, after it was rejected by Science and Nature over ethical concerns, Nature News reported.
Cut and paste. For the study, the researchers obtained 86 non-viable, early-stage embryos and injected them with a "gene-editing tool" called CRISPR/Cas9, an enzyme complex that binds to and snips specific sequences of DNA.
This technique has been used in previous studies to edit genes in the cells of animals and adult humans. Using it in embryos gives scientists the power to alter the genetic makeup of future generations. The team targeted a gene called HBB -- which is associated with the fatal blood disorder beta-thalassaemia -- and attempted to replace it with new genetic material.
A long way from designer babies. While the gene-editing tool successfully spliced DNA in 28 of the embryos, it only replaced the gene in a mere fraction of them -- and even introduced unwanted mutations into some. "Although it has attracted a lot of attention, the study simply underscores the point that the technology is not ready for clinical application," Dr. Jennifer Doudna, a biochemist at the University of California, Berkeley and a CRISPR/Cas9 pioneer, told The Huffington Post in an email. "And that application of the technology needs to be on hold pending a broader societal discussion of the scientific and ethical issues surrounding such use."
The researchers behind the new study agreed the technique isn't ready to be used in a clinical setting. "We still think it’s too immature,” study co-author Junjiu Huang, a gene-function researcher at Sun Yat-sen University in Guangzhou, told Nature News. He and his colleagues called for further research. "Our work highlights the pressing need to further improve the fidelity and specificity of the CRISPR/Cas9 platform, a prerequisite for any clinical applications of CRSIPR/Cas9-mediated editing," the team wrote in their paper.