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Why is the method used to change babies genetically so controversial? | Technology and Science | the science



On Sunday night the news shocked the scientific community: The Chinese scientist claimed that he successfully created the first genetically modified people using the CRISPR / Cas9 method.However, it is not clear to everyone what this technique consists of and why it causes so much noise, so we will explain the following to you.

In 1987, scientists from Osaka University, led by molecular biologist Yoshizumi Ishino, described repeated sequences in the genome of E.coli bacteria, but, although they described them, they did not understand their biological significance. Then, in the early 90s, the Spanish scientist Francisco J. Mozhika observed the same repetition in other unicellular organisms, the archaea Haloferax and Haloarcula.

Later, these repetitions were discovered in other archaic bacteria and mitochondria, and Mohica himself baptized them in the name CRISPR (from English: Clustered regular interval short palindromic repeats). It turned out that the sequences they were a form of adaptive immune system, the type of defense system by which bacteria store small segments of DNA in their genome, identical to those belonging to the viruses that attack them. If the bacteria are attacked again in the future, they immediately recognize the viruses and disable them.

Finally, researchers Jennifer Dudna and Emmanuel Charpentier found that by modifying a protein called Cas9, they can route and use a CRISPR sequence to cut DNA at a specific pointFrom this point on, it was possible to develop a cheap, relatively simple, but incredibly accurate tool for editing genes.

Simply put, CRISPR / Cas9 is a revolutionary molecular tool. used to edit or correct the genome of any cellThis is a kind of molecular scissors capable of cutting and cutting any DNA molecule accurately and in a controlled manner, eliminating or inserting a new one in order to activate or block the functions of the immune system.

— It could be a blessing … —

Although the revolutionary technology of genetic editing began to be used timidly in the dairy industry, it quickly moved to other areas. For example, it was tested to make nine calves born resistant to tuberculosis. This experiment was conducted only to verify the potential side effects of CRISPR / Cas9.

Later they followed a series of similar experiments that suggested the positive aspects of the technique. In May 2017, a group of American scientists managed to eliminate HIV from living mice, and the following month another American team said it was able to reverse the signs of Huntington's disease, in which brain cells die due to the release of toxic protein for the mutant version of the Huntingtin gene. In addition, in December of the same year, the technique prevented the development of amyotrophic lateral sclerosis (ALS) in mice.

However, CRISPR / Cas9 not only served to test hypothetical methods of treatment of animals, but also had more practical applications. Recently, a team of Argentine researchers modified potatoes to avoid spoiling too quickly, and after a few months, another team of American scientists changed small South American cherries to make it much more accessible.

— … or curse —

However, almost immediately after the mass adoption of CRISPR / Cas9, possible risks and hazards become more apparentIn May of last year, in a study published in Nature Methods, it was found that, despite the fact that this technique successfully corrected the gene that causes blindness in mice, it also caused the two animals to suffer more than 1,500 mutations and more than 100 inserts. and loss of genetic material.

A similar conclusion came from an analysis conducted in the United Kingdom, which found that the method seemed cause extensive mutations and genetic damage in human and mouse cellsThe most risky thing was that these unwanted changes would not be detected by existing DNA tests. “We found that changes in DNA were seriously underestimated,” explained geneticist Allan Bradley from the Wellcome Sanger Institute in the United Kingdom.

These were some of the reasons why, at the beginning of this month, Luis Montoloui, a researcher at the National Center for Biotechnology of Spain, explained that the genetic publication I was not ready to treat patients“It is not reasonable and unethical to justify putting patients at risk that we cannot yet control. Especially for in vivo treatment, in humans, ”said the scientist in an extensive article.

— Pandora's Box —

In this scenario, it was reasonable to limit genetic modification experiments only to bacteria, animals, or plants. Or at worst, for human embryos within 14 days.

That is why news coming from China caused a wave of stupor and condemnation. The most important representatives of biotechnology proved to be inconsistent with experiments conducted by researcher He Jiankui (who was removed from his university).

Julian Savulescu, director of the Center for Practical Ethics at Oxford University (UK), described the experiment as "monstrous"; and Joyce Harper, a specialist in reproductive medicine at University College London, said on the Nature magazine website that "these children are used as genetic guinea pigs."

For his part, Francisco Martinez Mohica himself, the discoverer of the Crispr-Cas9 technology, was skeptical of this feat and said in an interview with Onda Cero that “genetic modification is something that can be done, but it should not be done. to do ". For a scientist" something was done that, in the opinion of most scientists, should never be done ", besides:" It encourages a discussion that is open, it’s good that there is a debate, but it’s wrong that things are going as this man does. ”

— Less immediate risks —

However, in addition to individual risks, which, unfortunately, the twins of the Chinese experiment may suffer, there are other, much deeper ones for the rest of society. If CRISPR / Cas9 (or similar, such as CRISPR-GO) is improved to the extent that it can be safely used for people – and this is not properly regulated – we could be on the verge of a society learned from science fiction.

As historian Yuval Harari or his own adviser warned Stephen Hawking in his last book, nothing prevents people with better economic resources from choosing which characteristics their children have: better physically, smarter, faster, immune to disease or just more aesthetically attractive.

“There have always been differences between rich and poor: economic, political, social,” Harari told the conference recently. "However, with the advent of biotechnology, this will be the first time that these differences can become biological." Hawking suggested a similar scenario: “As soon as such supermen appear, there will be important political problems with unimproved people who cannot compete.”

It is true that we are still far from the scenario described by both thinkers. But given the speed with which these changes occur, it is most surprising to start discussing our pros and cons in a sensible way (for example: do we want to come in a kind of eugenics 2.0?). The ultimate goal is that the beneficiaries of progress are all members of society, not just a few … ordinary ones.

Source: N + 1

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