(Scientists modify genes of human embryos for first time in ‘secret’ experiments)
Chinese scientists have successfully edited the genes of human embryos for the first time, confirming rumours that secret genetic experiments had been happening in the country and prompting fears that the discovery could lead to a new kind of eugenics.
The researchers were able to successfully modify a specific gene responsible for a potentially fatal blood disorder. But they say that problems encountered during the testing mean that it is unlikely to be used more widely in the immediate future.
The technique could one day be used to edit out fatal and destructive genetic diseases. But others worry that it is unethical and could wreak unknown havoc on the human gene pool.
Using non-viable embryos obtained from fertility clinics, a group of scientists led by Junjiu Huang managed to inject embryos with an enzyme that can be programmed to target a specific gene. Along with another molecule that is also added to the embryo, that injection can repair or replace genes that are considered to be a problem.
The technique has been used in tests on human cells and animal embryos. But it is the first time that it is known to have been successfully tried on an embryo, and could make way for scientists to use the procedure to edit the genes of embryos used in IVF, before they are implanted.
The team tested the procedure on 86 embryos, and gave them 48 hours to react. After that it tested 54 of the 71 surviving embryos and found that 28 had been successfully spliced.
Scientists are worried that using the technique to snip out bits of DNA that are viewed as problematic could have terrible consequences for subjects’ descendants, as well as the concerns about a scientifically-enabled form of eugenics. Because the alterations will be coded into the “heritable line”, they will be passed down to future generations — and nobody is really sure what effect that would have over time.
Testing on humans steps over an ethical line about what we should be able to do to ourselves, Edward Lanphier, president of Sangamo and chairman of the Alliance for Regenerative Medicine in the US, wrote in a comment article for journal Nature earlier this year.
“We are humans, not transgenic rats,” Lanphier argued. “We believe there is a fundamental ethical issue in crossing the boundary to modifying the human germ line.”