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Everything was very fast. According to the Associated Press and the MIT Rechnology Review, a team of Chinese researchers claimed they managed to obtain the first two genetically modified babies with CRISPR born in November in Shenzhen (China), a few kilometers from Hong Kong. In a few hours, the University, the Hospital and part of the Chinese scientific community have tried to distance themselves from the experience. SUStech suspended his employment and salary.
Internationally, dozens of experts condemned the project as monstrous, irresponsible, dangerous, disappointing or premature . At this point, many doubts about what really happened but the debate is still topical. How is it possible that a single ad raises this dust? Are we facing one of the biggest bioethical and scientific debates of the decade?
According to available information and available documents, He Jiankui, professor of excellence at the South Shenzhen University of Science and Technology (China), and his team genetically modified an indeterminate number of embryos in seven in vitro fertilization processes. One of them, according to the team itself, came to an end throughout the month of November 2018.
The intervention concerned "canceling "the gene CCR5 which encodes a cytokine receptor for T cells of the immune system. To our knowledge, people with two copies of the delta32 mutation are resistant to HIV. This is a well-known variant because some experts regard it as one of the ten most "safe" modifications in order to begin to improve genetically human beings.
According to the researchers, resulted in two twins . ] one of which has the complete edition.The other is a genetic mosaic, that is to say that some of its cells have the CCR5 gene canceled and others not. During the day, several media tried to conform the birth, but confusion still prevails.
What is CRISPR?
In the summer of 2003, the bulb was lit on Mojica: it was one of Primitive Immune System . CRISPR was a molecular system that allowed prokaryotic cells to copy portions of viruses that attacked them to fight them in the future using a protein called Cas9.
This protein uses these virus fragments as "robot portraits" for . identify new microorganisms and attack them by cutting their genetic material to neutralize the threat. As Mojica himself told us in his interview: "When we discovered CRISPR, I thought," It's going to be crazy in biology "and then it's absolutely nothing ".
It took the team of Doudna and Charpentier nearly 10 years to point out that this same mechanism could be used to edit genomes . The idea was to use an artificial RNA to trick the Cas9 and use it to search for fragments of a genome and modify it at will.
This was the beginning of the revolution: in just a few months, not only was the intuition of the researchers confirmed, but also "it worked perfectly, much better than any other tool." And, moreover, was very easy to program ". In 2013, several research groups had already demonstrated in the laboratory that it worked in human cells
What is the use?
Paul Knoepfler, of the UC Davis School of Medicine, describes better than anyone else: CRISPR gives the impression that scientists feel like them. " a child a candy store ". On paper, the possibilities are enormous: securing the future of important micro-organisms for commercial use, reconstituting animal species or making genetic modifications to humanity in order to eradicate the worst hereditary diseases.
In addition, CRISPR-Cas9 opened the door to a new area of research that looks for other mechanisms to easily edit genomes. Genetic engineering has managed to move from remote science fiction to become a very fast developing field and full of opportunities.
And why do not we use it already?
The problem, explains Lluís Montoliu, l & One of the main Spanish authorities in this area, is that, although CRISPR is capable of doing wondrous things, other cell systems have more problems to adapt these changes. In very general terms: after an intervention with CRISPR, several cell repair systems act to "integrate" this change into the complete genomic sequence. This "integration" is sometimes perfect, sometimes neutralizing the intervention and at other times, it can give unexpected results.
This means that for the moment, experiments with CRISPR give very different results . When we talk about plants or animals, "those who carry the right sequence are chosen and the others are rejected". But with humans, for obvious reasons, it is not possible. Montoliu speaks of success in only 5% of cases .
Also, as we have already mentioned, early in 2018, Matthew Porteus warned that many of us already had antibodies against Cas9 and their use. this technique could give rise to very serious allergic reactions (including death) .
In Search of a Calculated Risk
At the present time, scientists are working at full speed to find solutions to these problems. But, for the moment, any genetic edition carries considerable risks . That is why they are only allowed when we talk about a serious illness and that the intervention is simple.
Like any other medical treatment, genetic intervention (whatever the technique) must be kept in a delicate balance between risks and benefits. The Chinese team claims to have acted on so-called genetic inactivation and it is the simplest and most effective application of all knowledge known so far. However, it is not without controversy because it is not a "medical" intervention (they are not trying to cure), we are confronted with an "improvement" of intervention .
So this is precisely the case that is so controversial. This involves the modification of the DNA of perfectly healthy embryos in order to immunize them against HIV. The change is colossal: we do not talk about curing diseases, we speak of "improving" the human species .
Human improvement? Eugenics?
