Editing the human genome: the first pancake lump
Chinese scientists have modified genes in a human embryo for the first time
Chinese geneticists admitted on the pages of a scientific journal that they had indeed modified the genome in a number of human embryos, rumors about which began to spread in early March, the press service of the website of the journal Nature (Chinese scientists genetically modify human embryos - VM) reports.
At the beginning of March this year, rumors began to creep in scientific circles that a number of Chinese scientists and their American colleagues had already conducted a number of experiments on editing and replacing genes in defective human embryos, as a number of unnamed molecular biologists told the editors of the Nature news service.
Today, these rumors have been confirmed – Chinese geneticists led by Junjiu Huang from Sun Yat-sen University in Guangzhou published an article this week in the journal Protein & Cell (Liang et al., CRISPR/Cas9–mediated gene editing in human tripronuclear zygotes - VM), in which they described the results in general quite unsuccessful attempts to adapt the rapidly gaining popularity of the CRISPR/Cas9 genome editing system for manipulating human DNA.
As the authors of the article emphasize, trying to reduce the degree of criticism, they used "dead" human embryos in such experiments, which they obtained with the consent of patients from local family planning and reproduction centers.
Huang and his colleagues tried to remove from their DNA the defective HBB gene that causes beta-thalassemia – a severe genetic blood disease that causes a lot of extremely unpleasant consequences: deformity of the skull and bones, mental retardation and a number of other problems.
As this experiment showed, CRISPR/Cas9 did not cope with the task – only 28 out of 86 embryos successfully survived genome editing, and only four of them became owners of the corrected version of the HBB gene. At this stage, geneticists were forced to stop the experiment, as they noticed that in addition to corrections in the right part of the DNA, CRISPR/Cas9 changed the structure of the genome in "unauthorized" parts of it.
According to the scientist, the results of these experiments were not published in the most prestigious scientific journals, such as Nature or Science, for the reason that their editors refused to accept the article "for ethical reasons."
Nevertheless, Huang does not plan to abandon the continuation of experiments – according to him, his scientific group is now working on creating more accurate and short-lived enzymes that will reduce the number of erroneous "edits". In addition, the problem may lie in the fact that the embryos used by geneticists contained three copies of chromosomes.
According to sources of the Nature news service, Huang is far from alone in this area – there are at least four other scientific groups in China that are conducting similar experiments. The results of their research may also appear on the pages of not the most famous scientific journals in the near future.
Portal "Eternal youth" http://vechnayamolodost.ru23.04.2015