A new technique for modifying genes

Publié le : 14 March 2014

 The French daily newspaper, Le Figaro, has reported on the development of a new technique by a Chinese team which can "target a gene in a cell and then modify it". In actual terms, the Chinese team has deactivated two genes in the Macaque monkey and "produced about twenty monkeys with both these modifications". ²        

Guillaume Pavlovic, team leader at the Institut clinique de la souris (ICS) (Mouse Clinical Institute) in Strasbourg explained that, "this new technique has allowed us to modify the genome of a primate in a controlled manner for the first time". 

The simplest method used to date involved introducing new genes into the cell, which would then penetrate the genome. This is precisely the method used to produce transgenic plants or for gene therapy. This new procedure, which was highlighted last February in the Cell journal, is based on a bacterial enzyme known as Case 9, the role of which was revealed in 2007 by scientists working in the dairy industry. In 2012, in the Science journal, an international team showed that the same enzyme could be "guided to cut a precise DNA sequence" by adding "a dash of genetic material to supplement the selected DNA sequence". This new technique can be used to produce "genetically modified animals or plants much more quickly". The relevant methods and programs required are supplied free of charge to laboratories, which explains the rapidity with which the Chinese team was able to perfect the method. 

For Guillaume Pavlovic, "this technique is in the process of revolutionising all our practices at lightening speed, generating greater certainty and efficacy along the way". However, as far as Jacques Testart is concerned, this new technique cannot modify the genetic characteristics of a human being. He recently expressed his concerns regarding eugenic spin-offs facilitated by embryo selection. Because, if it can modify a gene, "this process would only intervene in the early stage of fertilization, working on initial cells". This is a stage during which individual gene defects cannot be identified or repaired. Today, he stated that embryo sorting works at "approximately the eight cell stage, sampling two for further study. This Chinese technique cannot, therefore, be used to modify existing defects". On the other hand, added the biologist, it "seems more interesting to carry out gene therapy by correcting favourable mutations after birth".

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