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Sunday night, a story rocked the scientific community: A Chinese scientist claimed to have succeeded in creating the first genetically modified humans using a technique called CRISPR / Cas9 . However, not everyone understands this technique and why it causes so many problems, so we explain it below.
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 1990s, the Spanish scientist Francisco J. Mojica observed this same repetition in other unicellular organisms, Haloferax arches and Haloarcula.
Later, these repeats were detected in other archaic bacteria and mitochondria and the same. Mojica named them as CRISPR (from English: short palindromic repetitions regularly spaced). It turned out that the sequences were a form of adaptive immune system, a type of defense system by which bacteria store in their genome small segments of DNA identical to those of viruses that attack them. If the bacteria are attacked again, they will immediately recognize the viruses and eliminate them.
Finally, researchers Jennifer Doudna and Emmanuelle Charpentier discover that modifying a protein called Cas9 could direct and use the CRISPR sequence to cut the virus. DNA at a specific point . From there, it was possible to develop an inexpensive, relatively simple but incredibly accurate tool for editing genes.
In simple terms, CRISPR / Cas9 is a revolutionary molecular tool used to edit or correct the genome of any cell. . A kind of molecular scissors capable of cutting any molecule of DNA in a precise and controlled way, eliminating or inserting a new one to activate or block the functions of the immune system.
— It can be a blessing … —
Although the revolutionary technique of genetic modification began to be used timidly in the dairy industry, it quickly became from other areas. For example, it has been tested to make nine calves born resistant to tuberculosis. This experiment was conducted solely to test the potential side effects of CRISPR / Cas9.
Later, they followed a series of similar experiments suggesting the positive aspects of the technique. In May 2017, a group of US scientists succeeded in eliminating HIV from live mice, and the following month another US team claimed to have succeeded in reversing the signs of Huntington's disease, in which brain cells die. reason for a toxic protein released. for a mutant version of the huntingtin gene. In addition, in December of the same year, the technique made it possible to inhibit the progression of amyotrophic lateral sclerosis (ALS) in mice.
However, CRISPR / Cas9 has not only been used to test hypothetical treatments in animals, but more practical applications. Recently, a group of Argentine researchers modified the potatoes to avoid the damage too quickly, and a few months later, another team of American scientists modified a small cherry of South America to make it much more marketable .
— … or a curse —
However, almost immediately after the mbadive adoption of CRISPR / Cas9, the risks and potential dangers begin to become more obvious . In May, a study published in Nature Methods revealed that although the technique successfully corrected a gene responsible for blindness in mice, it also caused more than 1500 mutations and more than 100 insertions in two animals. and loss of genetic material.
A similar conclusion came from an badysis conducted in the United Kingdom, which revealed that the technique appeared to cause extensive mutations and genetic damage in human and mouse cells . The riskiest was that these undesirable changes were not detected by existing DNA tests. "We have discovered that DNA modifications have been seriously underestimated," said geneticist Allan Bradley of the Wellcome Sanger Institute in the United Kingdom
. This is one of the reasons why Luis Montolui earlier this month A research scientist from the National Biotechnology Center of Spain explained that genetic publishing n & # 39; Was not yet ready to treat patients . "It is neither prudent nor ethically justifiable to expose patients to risks that we are not yet able to control. Especially for therapies "in vivo", in the person, "said the scientist in a detailed article.
— Pandora's Box —
In this scenario, it was cautious of circumscribing genetic modification experiments solely on bacteria, animals or plants, or, in the worst case, to human embryos within 14 days
That is why news from China has generated a wave of stupor and condemnation.The main representatives of biotechnology have disapproved of the experiments of the researcher He Jiankui (suspended from his university).
Julian Savulescu, director of the Practical Ethics Center of the University of Oxford (UK) Kingdom), described the experience as "monstrous", and Joyce Harper, a specialist in reproductive medicine at University College London, said on the website of the Nature magazine that "this s babies are used as genetic guinea pigs ".
For his part, Francisco Martínez Mojica, discoverer of the Crisp-Cas9 techniques were skeptical about the feat and pointed out in an interview to Onda Cero that "genetic modification is something that can be done but should not be done. " For the scientist, "something has been done which, according to most scientists, should never be done", besides, "This encourages an open debate, it is good that there is a debate, but it It's not fair that things are done as they do this man. "
— The less immediate risks —
However, beyond the individual risks that, unfortunately, twins can undergo Chinese experience, there are others much deeper for the rest of society. If the CRISPR / Cas9 (or similar devices like the CRISPR-GO) is perfected to the point that it can be used safely in humans – and that it is not properly regulated – we could find ourselves at the door of a society derived from science fiction. [19659002] As historian Yuval Harari or Stephen Hawking himself warned in his latest book, nothing can prevent people with better economic resources from choosing the characteristics of their children : better physically, smarter, faster, immune to disease or simply more attractive from an aesthetic point of view.
"There have always been differences between the rich and the poor: economic, political and social," Harari recently told a conference. "However, with the advent of biotechnology, it is the first time that these differences can become biological". Hawking imagined a similar scenario: "Once such superhumans appear, there will be significant political problems with unimproved humans, who will not be able to compete."
It is true that we are still far from the scenario described by the two thinkers. The speed with which all these changes occur, the wisest is to begin to debate now intelligently its pros and cons (eg: do we want to come up with a kind of eugenic 2.0?). The ultimate intention is that the beneficiaries of progress are all members of society and not just a few … the usual ones
Source: N + 1
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