A year after the first genetically-engineered human embryos were created in China, a different Chinese team has repeated the experiment, with much the same results: failure.
Researchers from Guangzhou Medical University gathered 213 surplus IVF embryos which were not viable because they had an extra chromosome. Using the CRISPR–Cas9 technique, they spliced into the genome of 26 embryos a mutation that protects people against the HIV virus. After three days they destroyed the embryos.
The experiment was published in an obscure outlet, the Journal of Assisted Reproduction and Genetics.
The results were by no means spectacular. The technique only worked in 4 embryos. And the modification was not present in all of the chromosomes and in some cases, other mutations were introduced.
Harvard stem-cell scientist George Q. Daley told Nature, “This paper doesn’t look like it offers much more than anecdotal evidence that it works in human embryos, which we already knew.”
Some scientists were uneasy about the ethics of the experiment. Even the authors concluded that “We believe that any attempt to generate genetically modified humans through the modification of early embryos needs to be strictly prohibited until we can resolve both ethical and scientific issues.” One scientist asked why experiments like this were not being done on primates first. Another said that even though the ethics paperwork had been done, “Introducing [a gene] and trying repair, even in non-viable embryos, is just playing with human embryos.”
Dr Daley also questioned the need for the experiment: “the science is going forward before there’s been the general consensus after deliberation that such an approach is medically warranted.”
However, Nature News says that scientists believe that similar research in going on in several labs in China.