Green light given to controversial experiment.
Scientists in Britain have been granted permission to perform controversial experiments that will create human embryos using genetic material from three people. Teams carrying out similar research in the United States and China have been forced to shut down their experiments, and say that they hope the UK decision will help push the work forward around the world.
The UK Human Fertilisation and Embryology Authority (HFEA) said on 8 September that it will allow scientists at the University of Newcastle upon Tyne to transfer the nucleus of a fertilized egg into an egg donated by a second woman. The second egg's own nucleus will be removed before the transfer occurs, but it will still contain genetic material in certain structures outside the nucleus. These structures, called mitochondria, generate energy and carry their own genes. So the Newcastle scientists will be creating embryos that contain genes from three people: the biological mother, the biological father and an unrelated egg donor. That makes the experiments highly controversial.
The embryos that will be created in Newcastle will not be transferred into women. But advocates of the technique say that if the experiments work, they could eventually prevent mothers from passing on diseases caused by mitochondrial defects to their children.
Similar experiments were being done in the United States by James Grifo, a reproductive endocrinologist at New York University Medical Center. But in the late 1990s the US Food and Drug Administration (FDA) halted Grifo's experiments after he had created only a few embryos, because it was worried that the health of the fetuses could not be guaranteed. Grifo's postdoctoral fellow, John Zhang, continued the experiments in China, where altered embryos were transferred into two patients before an international outcry shut those experiments down too. Grifo, who has since been pleading with the FDA to allow him to restart the experiments, told Nature that he is encouraged by the HFEA's decision.
“I'm glad that at least one country in the world is pioneering and smart enough to do this, and hopefully it will help patients with mitochondrial diseases,” Grifo says.
He predicts that the British move will eventually spur action elsewhere, including in the United States. “Once there's some semblance of success over there, they'll say ‘OK, now we can do it.’ Traditionally, that's how things go.”
More than 30 children have already been born thanks to a related technique that is used to boost fertility. The method does not involve nuclear transfer — instead, scientists transfer some of the cytoplasm that surrounds a cell's nucleus from a donor egg to the fertilized egg. But that method has also been halted in the United States, leaving the Newcastle researchers at the head of the field, for the moment at least.
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British Medical Bulletin (2015)
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