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Sunday night, news shook the scientific community: A Chinese scientist claimed to have successfully created the first genetically modified humans using a technique called CRISPR / Cas9. However, not everyone knows what this technique is and why it causes so many problems, so let's explain it to you.
In 1987, scientists at Osaka University, led by molecular biologist Yoshizumi Ishino, described repeated sequences of the genome of E. coli 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, the archaea Haloferax and Haloarcula.
Later, these repetitions were detected in other archaic and mitochondrial bacteria and Mojica himself named them with the name of CRISPR (from English: Clustered Reginders Palindromic Short Regs regularly interspaced). It turned out that the sequences they 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 viruses that attack them. If bacteria are attacked again, they will immediately recognize the viruses and eliminate them.
Finally, researchers Jennifer Doudna and Emmanuelle Charpentier discovered that by modifying a protein called Cas9, they could route and use the CRISPR sequence to cut DNA at a specific point. From there, it was possible to develop an inexpensive, relatively simple but incredibly accurate tool for gene editing.
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 genetic editing technique began to be used timidly in the dairy industry, it quickly shifted to 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. Moreover, in December of the same year, this 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 has had 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 massive adoption of CRISPR / Cas9, the risks and possible dangers began 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.
At the same conclusion, an analysis conducted in the United Kingdom revealed that the technique seemed 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.
These are some of the reasons why, earlier this month, Luis Montolui, a research scientist at the National Biotechnology Center in Spain, explained that genetic editing I was not 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 "in vivo" therapies, in the person, "said the scientist in a complete article.
— Pandora's box —
In this scenario, it was prudent to limit genetic modification experiments to bacteria, animals, or plants. Or in the worst case, to human embryos up to 14 days.
That's why news from China has generated a wave of stupor and condemnation. The most important representatives of biotechnology have disagreed with the experiments conducted by researcher He Jiankui (suspended from his university).
Julian Savulescu, director of the Practical Ethics Center at Oxford University (UK), described the experience as "monstrous"; and Joyce Harper, a specialist in reproductive medicine at University College London, told Nature's website that "these babies are used as genetic guinea pigs".
For his part, Francisco Martínez Mojica himself, discoverer of Crispr-Cas9 techniques, was skeptical of the feat and said in an interview with Onda Cero that "genetic modification is something that can be done, but should not be done, do it. "For the scientist," something has been done that most scientists believe should never be done ", in addition," This encourages open debate, it is good that 'There is a debate, but it's not fair that things are done like this man does.'
— The least immediate risks —
However, beyond the individual risks that unfortunately can be experienced by the twins of the 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 be at the doors of a society out of science fiction.
As historian Yuval Harari or his own adviser had warned him Stephen Hawking 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 diseases or simply more attractive from an aesthetic point of view.
"There have always been differences between rich and poor: economic, political and social," Harari recently said at a conference. "However, with the advent of biotechnology, it is the first time that these differences can become biological." Hawking envisioned 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. But given the speed with which these changes occur, the wisest thing is to start discussing intelligently now its advantages and disadvantages (for example: do we want to arrive in a kind of 2.0 eugenics?). 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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