A quick guide to understanding how CRISPR can change the future of the human species
Why are we still talking about CRISPR?
The news of the week was undoubtedly the birth of two Chinese twins (Lulu and Nana) whose DNA was genetically modified by CRISPR . Jiankui He, professor of excellence at the South Shenzhen University of Science and Technology, China, and his team have genetically modified fifteen embryos of nine volunteer pairs to obtain embryos with the mutation desired. According to the team itself, the first successful pregnancy would have been completed in November 2018 and the second would come out of the accounts in the next few months.
The intervention was aimed at "reversing" the CCR5 receptor gene that has a very close relationship with the T cells of the immune system. In summary, 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 "safer" modifications in order to begin to improve genetically the man.
The result, again according to the researchers, was not entirely satisfactory. one of the girls has the complete edition, the other is a genetic mosaic (that is to say that some of its cells have the cancellation of CCR5 and others not ) but no matter, if this is confirmed, we will face the first case of human improvement, a line that no one had yet dared to cross.
How did we manage to do all this?
To understand it, we have to go to Salt marsh of Santa Pola, Alicante, in the 80s. There, a young Spanish researcher, Fracis Mojica, found strange repetitions. in the DNA cells that pa They are very important, although I do not understand why. It took more than 20 years to understand that it was a molecular immune system.
When a virus enters a prokaryotic cell (cells possessing the genetic material scattered through the cytoplasm), they catch it and use it for their own purposes in as long as MacGyver in a case. For this reason, at the cellular evolution there was no other remedy than to create systems to fight them. This is CRISPR: a system that allows for "robotic portraits" of viruses and to use a protein (called Cas9) to identify and neutralize them by cutting their genetic material.
In 2012, a Franco-American research team discovered that we could use RNA. artificial to cheat proteins. Thus, we could make him look for fragments of the genome of the cell and edit them at will. In addition, we discovered that it was the simplest, cheapest and most accurate system we have ever encountered.
It turned out that with CRISPR, we could almost do anything: carry out experiments that we could not even imagine until now, ensuring the future of micro-organisms recover extinct species or genetically modify people. In technical terms, it can be said that this is the "lemon pear" and that in the last decade, we have devoted more and more resources to its in-depth understanding.
What's there to understand? Why do not we use it already?
The problem is that it is a technique with a lot of potential but it is "in its infancy": we still know very little. You see, CRISPR-Cas9 is a very accurate tool that publishes the genome, but is not the only mechanism involved in the process and those who do it are not so accurate.
The cells in our bodies have molecular systems that cross DNA in search of possible errors or accidental damage. When they detect one, they try to fix it. This means that after each edition, there are several mechanisms that check the genome errors and, if they think, they can "correct" our work: this correction can leave the edition intact, it can be reset or can introduce very dangerous changes. . This is a lottery .
This is the big problem of CRISPR. To give an idea, when we work with mice, the success rate is about 5% . In other words, only 1 of 20 published mice have the desired modification. In science, the solution is simple: the mice that do not "use" in quotation marks are excluded from the search. With humans, we can not do that.
And that's just one of the problems we know (and we still need to know). For example, over the past year, studies have been conducted on possible allergic reactions that can kill patients. Until we are certain of the dangers of the technique, it is dangerous to go farther .
But is not that what happened in China?
It is precisely and that is what makes the Chinese case so controversial. The researchers took embryos in perfect health and modified them to avoid any possibility of infection. From where many experts call him imprudent . However, he put on the table a subject that goes further.
Now that we have a tool that will allow us to do incredible things with our genes, should we use it? Most bioethics experts agree that, as if it's a treatment, use the tools we have available to to end the disease and to human suffering is a good idea
A thorny debate arises when we are talking not about healing, but about improving people. Questions accumulate should we change our children to be taller, smarter, or smarter? Should we make them stronger, better dancers and skillful with the crafts?
Some people think we should do it. Julian Savulescu is a renowned philosopher who advocates "procreative beneficence", that is, the ethical responsibility of parents to use these techniques to offer their children the best opportunities (also in the genetic field) .
In fact, there are Some researchers, like George Church, a professor of genetics at Harvard University, have lists of genetic modifications that they feel are good enough and safe enough to start at the university. Introduce to our children as soon as possible. But these are just the most daring voices.
Are not most experts on this line?
Neither the majority of experts, nor most of the countries . It is precisely for this reason that China has been chosen for this experience. In the Asian giant, unlike in other countries, it suffices that the ethics committee of a hospital approves the experience (which seems to have been done) so that you can start to work with her. As a result, China has been publishing patients with CRISPR since 2015, while the rest of the countries are experiencing delays and delays. remote And what will happen now
