14 DAY TRIAL // Scientists working with the Sun Yat-Sen University in Guangzhou, China, claim to have genetically modified several laboratory-made human embryos. The research project, detailed in a paper in the journal Protein & Cell, is hailed as a world first.
Although this probably wasn't the team's intention, the news about the making of the first ever edited human embryos has sparked a heated discussion about how the technique used by the Sun Yat-Sen University could lead to designer babies and the ethics of it all.
How the embryos were genetically altered
In the report detailing their work, the Chinese scientists explain that the embryos they worked with were obtained from local fertility clinics in the city of Guangzhou in China and that they were all non-viable, meaning that they were abnormal and couldn't have resulted in a live birth.
To alter their genetic makeup, the researchers treated the embryos with an enzyme complex dubbed CRISPR/Cas9, which allowed them to cut and bind DNA at specific locations.
Having injected the embryos with CRISPR/Cas9, the Sun Yat-Sen University specialists managed to edit a gene dubbed HBB. The reason they targeted this gene and not some other one was because the study was intended to test DNA editing as a means to tackle genetic diseases.
Thus, investigations carried out over the years have shown that mutations in the HBB gene correlate with a potentially fatal blood disorder known as β-thalassaemia. Hence, editing the problematic gene means eliminating the risk for this disease.
When subjected to genetic editing, the human embryos all comprised just one cell. Once treated with the CRISPR/Cas9 enzyme complex and provided with the molecules needed to replace the removed genetic material, they were left to their own devices for 48 hours.
Not a very impressive success rate
Following the rest period, the scientists checked up on their Petri dishes and found that, of the 86 embryos they experimented on, a total of 71 survived the procedure. Of these embryos, only 28 showed signs of proper DNA breakage and just 7 contained the replacement genetic material.
While just 7 of the human embryos were genetically altered according to plan, many others displayed mutations that the researchers never wanted to happen. Consequently, the study was halted.
“If you want to do it in normal embryos, you need to be close to 100%. That’s why we stopped. We still think it’s too immature,” researcher Sun Yat-Sen University Junjiu Huang told the press in an interview, as cited by Nature.
“Their study should be a stern warning to any practitioner who thinks the technology is ready for testing to eradicate disease genes,” added specialist George Daley with the Harvard Medical School in Boston, who was not involved in the study.
The pros and cons of genetic engineering
Those who support such practices argue that genetically engineering human embryos can help eradicate all sorts of devastating diseases that are due to an individual's faulty DNA and that cannot be treated or cured in any other way than by doing away with the genes that cause them.
Then again, others argue that genetic modifications done to human embryos are bound to propagate to future generations and can end up birthing an entirely new generation of genetic diseases. Besides, there are ethical hurdles that come with editing a human embryo's DNA.