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Why is the technique used to modify babies genetically controversial? | Technology and science | science



On Sunday night a news rocked the scientific community: A Chinese scientist claims to have succeeded in creating the first genetically modified human using a technique called CRISPR / Cas9. However, it is not clear to everyone what this technique consists of and why it causes a lot of noise, so we explain it to you next.

In 1987, scientists from Osaka University, led by molecular biologist Yoshizumi Ishino, described the repetitive sequence in the genome of E. coli bacteria, but even though they described it, they failed to understand their biological significance. Then, in the early 90's, Spanish scientist Francisco J. Mojica observed this same repetition in other unicellular organisms, Archaea Haloferax and Haloarcula.

Then, this repetition was detected in other archaic bacteria and mitochondria and Mojica themselves baptized them by name CRISPR (from English: Clustered Regularly Intervert Short Palindromic). Apparently the order they are a form of adaptive immune system, a type of defense system where bacteria store small segments of DNA in their genomes identical to the viruses that attack them. If the bacteria is attacked again in the future, they immediately recognize the virus and cut it off.

Finally, researchers Jennifer Doudna and Emmanuelle Charpentier discovered that by modifying a protein called Cas9 they can route and use the CRISPR sequence to cut DNA at a certain point. From this point on, it is possible to develop inexpensive, relatively simple but very accurate tools for editing genes.

Simply put, CRISPR / Cas9 is a revolutionary molecular tool used to edit or repair any cell genome. A kind of molecular scissors that is capable of cutting any DNA molecule in a precise and controlled manner, removing or inserting new ones to activate or block the function of the immune system.

— That can be a blessing … —

Although the editing techniques of revolutionary genetics began to be awkwardly used in the dairy industry, he quickly turned to other fields. For example, it was tested to make nine calves born immune to tuberculosis. This experiment was conducted only to test the potential side effects of CRISPR / Cas9.

Then, they followed a series of similar experiments that suggested positive aspects of the technique. In May 2017, a group of American scientists succeeded in removing HIV from living 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 because of the toxic protein released. for the mutant version of the Huntingtin gene. In addition, in December of the same year the technique served to inhibit the development of amyotrophic lateral sclerosis (ALS) in mice.

However, CRISPR / Cas9 does not only function to test hypothetical treatments in animals, but has more practical applications. Recently, a group of Argentine researchers modified potatoes to avoid decay too quickly, and a few months later another team of American scientists modified small South American cherries to make them more valuable.

— … or curse —

However, soon after the mass adoption of CRISPR / Cas9, risks and dangers that might begin to become clearer. In May last year, a study published in Nature Methods found that, although the technique succeeded in correcting the gene that caused blindness in mice, it also caused two animals to suffer more than 1500 mutations and more than 100 insertions. and loss of genetic material.

For a similar conclusion came an analysis carried out in England, which found that the technique appeared causing extensive mutations and genetic damage in human and rat cells. The most risky of these unwanted changes will not be detected by existing DNA tests. "We found that changes in DNA have been seriously underestimated," explained geneticist Allan Bradley of the Wellcome Sanger Institute in the UK.

Here are some reasons why, earlier this month, Luis Montolui, a scientific researcher at the Spanish National Biotechnology Center, explained that the genetic edition I am not ready to treat patients. "It is unwise and unethical to justify exposing patients to risks that we cannot control. Especially for therapy & # 39; in vivo & # 39 ;, for that person," the scientist said in a broad article.

— Pandora's Box —

Put in this scenario it is wise to limit genetic modification experiments only to bacteria, animals or plants. Or in the worst case, a human embryo is within 14 days.

That's why the news coming from China has resulted in a wave of fainting and curses. The most important representatives of biotechnology have shown their disapproval with experiments conducted by researcher He Jiankui (who has been suspended from his university).

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

Meanwhile, Francisco Martínez Mojica himself, the inventor of the Crispr-Cas9 technique, was skeptical of the achievement and said in an interview to Onda Cero, that "genetic modification is something that can be done, but it cannot be done." For scientists, " something has been done, according to most scientists, it should not be done ", in addition," This encourages open debate, it's good to have a debate, but it's not true that things are done like this person does. "

— Less risk soon —

However, it is beyond the risk of individuals who, unfortunately, twins from Chinese experiments may suffer, there are others who are far deeper for other societies. If CRISPR / Cas9 (or something like CRISPR-GO) is perfected to the point that it can be used safely in humans – and this is not properly regulated – we can be on the doorstep of society drawn from science fiction.

As historian Yuval Harari or his own advisor warned Stephen Hawking in his last book, nothing can prevent those who have economic resources better than choosing what characteristics their children have: better physically, smarter, faster, immune to disease or more aesthetically appealing.

"There is always a difference between rich and poor: economic, political, social," Harari recently said at the conference. "However, with the advent of biotechnology, this is the first time these differences can become biological." Hawking imagined a similar scenario: "once supermen appears, there will be important political problems with unwanted 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 of this change, the wisest thing is to start arguing now pros and cons in a smart way (for example: do we want to arrive in a kind of eugenics 2.0?). The final intention is that beneficiaries of progress are all members of the community and not just some … ordinary ones.

Source: N +1

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