End of 2018. Chinese scientist He Jiankui announces to the world that he has used the CRISPR technique – the so-called gene editing – to modify the CCR5 gene of twins Lulu and Nana (in their embryonic phase), with the aim of making them resistant to HIV , cholera and smallpox. It was carried out outside the law and without consulting anyone.
The news shocked the scientific community. Apart from technical problems – it is not yet known if the method is completely safe – a crucial ethical dilemma arises: is it legal to create human beings à la carte?
Now, an analysis by scientists at the University of California at Berkeley affects the health risks: the mutation of the CCR5 gene is linked to an increase in mortality in later life. Lulu and Nana are protected against HIV, but when they reach middle age they are more likely to die than other people.
This conclusion arises from the analysis of 400,000 genomes stored in the British UK Biobank database. The Berkeley researchers scrutinized it and found that individuals between the ages of 41 and 78 who have two mutated copies of this gene have a 21% higher mortality rate than those who have one copy or none.
Unethical and reckless
Speaking to the SINC Agency, Danish biologist Rasmus Nielsen, professor at the University of California at Berkeley and director of the research, points out that “we do not know the details of the He Jiankui experiment, but there are many reasons to say that it was unethical. and reckless. Our study emphasizes that mutations such as that of the CCR5 gene can have beneficial effects in one context, but negative in others. It is difficult to predict all the possible consequences of a mutation. And this should be taken into account in any experiment that uses genetic modification in humans ”.
The gene involved encodes a protein on the surface of immune cells that collaborates with HIV and helps it enter them. The modification made by the controversial Chinese geneticist mutates the gene and cancels that characteristic of the protein.
To achieve this, He Jiankui relied on the CRISPR technique. How does this gene editing method work in embryos? Simplifying a lot: molecular scissors formed by proteins are used that look for a specific sequence of DNA and cut it. That embryo with the modified DNA continues its development and, if all goes well, it gives rise to a person with the desired genetic modification, which it will also transmit to its possible descendants.
The procedure is dangerous, because much remains to be known about the workings of DNA and the interaction of its genes, and the work of the Berkeley scientists confirms these fears. In addition, most researchers are against using this method without prior controls and a rigorous ethical review. In fact, last March, 18 scientists from seven countries who are experts in CRISPR and ethics requested in an article published in Nature that a five-year moratorium be set for gene editing projects of sperm, egg or embryo DNA, intended to create genetically modified babies.
