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A scientist in China may have used a powerful gene editing tool to extract unwanted genes from human embryos, creating the first genetically modified human being, bringing a dystopian future so much feared by many.
The scientist, He Jiankui, said in a video that he published online Yesterday (November 25), he used CRISPR-Cas9 – a gene editing tool that has revolutionized the field of genetics over the last decade – to remove a gene from human embryos to make babies resistant to HIV. He said in the video that these embryos have become two healthy babies: a set of twins named Lulu and Nana. The twins "came screaming into the world as healthy as all the other babies a few weeks ago," he said in the video.[[[[Genetic by the Numbers: 10 Tasty Tales]
The complaint of the scientist has not yet been verified – in fact, the hospital named in the ethics approval document of He denied any involvement in the proceedings, reported CNN – but the scientific community has always responded to the complaint with indignation and concern, according to reports to the press. Indeed, even leaving aside the very real ethical concerns of using this technology to manipulate human genes, many scientists believe that such changes could lead to large-scale and unexpected health problems.
It is true that the modification that he brought to the embryos "will prevent HIV infection," said Mazhar Adli, a geneticist at the University of Medicine's Faculty of Medicine. Virginia. The problem, however, is that the deleted gene, called CCR5, "has many more functions than just help with HIV infection," Live Science said, including helping white blood cells to function properly.
The gene could also play a role in preventing infection with West Nile virus, so cutting it off from the genome makes a person more susceptible to the disease, said Feng Zhang, of the Broad Institute, in a press release issued in response to this news. Zhang was one of the scientists who was the first to use CRISPR gene modification technology.
In addition, genes do not exist in isolation – they interact constantly with other genes, which can have major effects on the body. "The deletion of a single gene can not only alter the functioning of other genes, but also alter the general behavior of the cell and the phenotype of [the] organism, "said Adli (A phenotype is an observable characteristic, such as brown eyes, that someone has on the basis of the genotype, or genes, which code it).
And these concerns are motivated by problems that can arise when it is assumed that CRISPR technology will work perfectly and accurately. Unfortunately, this is unlikely to be the case: in July, scientists published an article in Nature Biotechnology that showed that the use of CRISPR-Cas9 technology may be more damaging than thought previously, by unintentionally modifying large pieces of DNA.
"You have to use this technique very wisely because it is associated with many problems," said Dr. Avner Hershlag, head of Northwell Health Fertility in Manhasset, NY. Thus, reaching and suppressing this gene could have unexpected off-target effects elsewhere in the genome. In other words, the Cas9 protein that you program to remove a site could move to another site in the genome and make changes you did not want, Hershlag told Live Science. But it is highly unlikely that the scientist realizes that these untargeted changes have occurred. They may not appear before the baby is born, or later in life, he said.
There are "major genetic conditions that only occur later in life," Hershlag said. And these genetic changes can be passed on to future generations, he said.
There is also a risk of mosaicism, Hershlag said. Normally, body cells carry the same identical set of genes, but mosaicism refers to a scenario in which some cells, but not all, carry a genetic change due to gene editing, Hershlag said. It's something that, in itself, can lead to disease, he added.
Adli and Hershlag also pointed out that, in terms of HIV prevention, there are safer (and easier) ways to do this. For example, the PrEP treatment method, which is taken daily, has been shown to be effective in preventing infection in major trials. And other treatments may be on the horizon.
Thus, added Adli, "who will take responsibility for these future babies when their peers will be treated with a simple pill and survive happily, but that those whose genome is modified know all the challenges ahead [side] effects?"
Originally published on Science live.
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