Embryo gene therapy: a new step
In China, the DNA of viable human embryos has been successfully corrected
Anatoly Glossev, Vesti
Biologists have edited the DNA of human embryos, ridding them of a severe hereditary disease – Marfan syndrome. The achievement is reported by a scientific article published in the journal Molecular Therapy by a group led by Xingxu Huang from the Shanghai Institute of Biochemistry and Cell Biology.
In the new work, the scientists used a more modern version of the CRISPR genome editing technology. Unlike the standard technique, in this case, the DNA molecule is not cut in an arbitrary place, after which the desired fragment is inserted. Instead, it only changes one nucleotide to another in the selected place of the genome. This greatly limits the scope of applications, but seriously reduces the percentage of errors.
The embryos selected for the experiment had a mutation leading to Marfan syndrome. This disease is characterized by multiple disorders in the development of the skeleton, muscles, internal organs, and so on. The root of the problem lies in the FBN1 gene, in which, instead of the guanine nucleotide (G), such people have adenine (A).
The CRISPR version, which replaces individual nucleotides, came in very handy here. The scientists replaced DNA A in the defective section with G. And, as further research showed, the procedure was successful for all 18 embryos.
However, there were some overlays. As the resource notes phys.org , in two embryos, the substitution occurred not only in FBN1, but also in some other genes. These embryos were found by standard IVF methods of screening out "unsuccessful" embryos. Genome sequencing did not reveal any defects in all other embryos. That is, in the end, scientists got quite healthy embryos, and they could implant them into a woman's uterus if they wanted to.
Of course, the biologists did not do this. Editing human DNA is a completely new field, little studied from a scientific point of view and very problematic from an ethical point of view. Therefore, much more research is needed to one day allow a genetically modified embryo to develop into a fetus.
Recall that the first experiments with gene modification in human embryos were carried out in 2015. However, then it was about interfering with the DNA of a triploid embryo, which in any case was not viable.
A year later, the news about the change in the genome of human embryos spread around the world again. It caused a great resonance, despite the fact that the successes were modest: then only about one in ten embryos subjected to the procedure received corrected genes (only four would have been suitable for potential implantation into the uterus).
In 2017, in China and then in the USA, scientists also edited the DNA of viable human embryos.
It is important to note that all experiments on human embryos are carried out with "spare" embryos left after IVF procedures (they are subject to destruction in any case). Nevertheless, some experts draw attention to the possible unpredictable consequences of experiments to change the human genome and call for their ban.
Portal "Eternal youth" http://vechnayamolodost.ru