Chinese researchers manipulated genetic material of embryos with severe consequences

The creation of a "designer baby" with the desired hair and eye color, a high intelligence quotient - and of course no hereditary diseases - is still the highest goal of some genetic researchers. For others, it is almost a horror idea to want to create a supposedly perfect child. Especially the way there - numerous experiments on human embryos - is rejected for ethical and moral reasons by most experts. In this country, gene experiments on fertilized human embryos are therefore prohibited. In China, such manipulations may be carried out against it. Scientists at Sun Yat-sen University in Guangdong have now intervened in the DNA of embryos for the first time, thereby breaking the taboo in genetic engineering - with fatal consequences. The study results were published in the journal "Protein & Cell".

Scientists performed genetic engineering on fertilized human embryos
The researchers performed gene experiments on 86 non-viable embryos from a fertility clinic. The embryos were falsely fertilized by two spermatozoa and would therefore only reach the early stage of growth before dying. The applied method is called "CRISPR / Cas9" and has already been tested on mouse embryos and adult human cells, according to the online edition of "Nature"..

According to the magazine, the researchers wanted to change a gene that can cause the severe blood disorder "beta-thalassemia". The first tests were carried out two days after the genetic manipulation on 54 embryos. It would have been shown that only 28 of them had grown and only a very small proportion had taken up the new genetic material. This failed the attempt.

But it got worse. At the same time, a large number of unexpected mutations in the DNA of embryos have developed, which were first caused by the "CRISPR / Cas9" method, according to the science magazine. Thus, the damage was much greater than in previous studies on mice and human cells. The defects could be due to the researchers using defective embryos. But even study leader Junjiu Huang admitted to the magazine: "If you want to do that with normal embryos, you have to be one hundred percent sure. That's why we stopped. The method is still too immature. "

Many experts criticize the approach of the Chinese gene researchers
"I believe this is the first report on CRISPR / Cas9 in human preimplantation embryos and, as such, the study is a milestone, but also a cautionary one," said George Daley, a stem cell biologist at Harvard Medical School in Boston, Massachusetts. Nature ". "The study should be a serious warning to any practitioner who thinks the technology is ready for the test to eradicate disease genes."

It is rumored that four research teams are currently experimenting with human embryos in China alone. "We need to stop our research and have a broad discussion about where we want to go," Edward Lanphier warned in the magazine. Many critics fear that the intervention on the embryo could trigger mutations that not only have unpredictable consequences, but could also be inherited. Also, the so-called genetic selection is seen extremely critical. Through them, it could eventually be possible to create "designer babies". Adverse features of a child would then be eliminated already in the early embryo stage.

According to the magazine, after the failure Huang wants to focus on refining the methods of gene manipulation so that the unwanted mutations can be further reduced. This requires studies on animals and adult human cells. However, Lanphier fears that other researchers will now try to continue Huang's embryo study: "Scientists all over the world now have the opportunity to conduct their own experiments in this direction." (Ag)

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