Western scientists and ethicists are questioning a Chinese genetic experiment in which researchers claimed to have edited DNA, the human blueprint, for the first time.
Chinese researchers said they used human embryos as subjects in manipulating genes in a way that could be passed on permanently, the Wall Street Journal reported Friday.
The practice is being hotly opposed by most genetic researchers and ethicists around the world.
The technique allows genes to be deleted or added to the DNA in the nucleus of cells — changes that would permanently alter the DNA and have the potential to be passed down to future generations.
It is seen as a promising procedure to fix defective genes in mature cells, where repairs don’t become integrated into a patient’s inherited DNA.
Chinese researchers published a scientific paper detailing their application of the technique to human embryos, in what experts believe is a world first.
According to the April 18 paper in the journal Protein & Cell, the scientists tried it on 86 human embryos they had obtained from a fertilization clinic.
In each, they attempted to repair a gene that causes the hereditary blood disease beta-thalassemia.
All but a few of the embryos survived the procedure but subsequent testing showed that the gene repair failed to make the desired changes and caused what the geneticists called “off-target” effects.
Scientists and ethicists have hotly debated the use of such technologies, which make changes to the so-called germ-line of cells.
One worry is that babies born via genome editing would have had their genetic makeup altered without consent.
A more futuristic concern is that elaborate tinkering with the human genome might usher in an era of designer babies with specific traits, such as blond hair or green eyes, that offer no medical benefit.
The International Society for Stem Cell Research in the United States issued a statement Thursday in response to the Chinese study, calling for a moratorium.
It wants to discourage attempts at human clinical germ-line genome editing while extensive scientific analysis of the potential risks is conducted, along with broad public discussion of the societal and ethical implications.
Peter Mills, assistant director of the Nuffield Council on Bioethics in Britain, urged caution about the technology because the paper suggested that the technique did not work as well in human embryos as it had previously in animal studies, suggesting that the tool may be more complex than previously understood.
“It sends a kind of warning shot about the need not to move forward impetuously into treatment” with such techniques, said Dr. Mills in a phone interview.
The Chinese researchers were from institutions including Sun Yat-sen University in Guangzhou, and the Guangdong Province Key Laboratory of Reproductive Medicine.
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