A large number of scientists around the globe have been talking about the importance of the stopping the studies involving genetic editing of human embryos. Now, the call for the halt has become even stronger as a Chinese team has recently succeeded in genetically engineering human embryos. This news was first reported on Wednesday by Nature News.
The said study was led by Sun Yat-sen University’s gene function researcher Junjiu Huang, who was ably supported a group of Chinese scientists.
The researchers have explained the process adopted by them for editing genomes of human embryos acquired from a fertility clinic. The collected embryos were nonviable and their chances of resulting in live birth were zero as they carried an additional set of chromosomes because of being fertilized by a couple of sperms.
The Chinese researchers tried to modify a gene that according to them was responsible for beta- thalassemia; for those who don’t know: thalassemia is an inherited recessive blood disorder marked by abnormal hemoglobin formation. They carried out the modification using a gene-editing technique called CRISPR/Cas9.
As many as 86 embryos were injected by the researchers; following this, they waited for 48 hours to allow the molecules replacing the missing DNA to begin its operations. Out of the 86 embryos, 71 managed to survive; tests were carried out on 54 of them.
During the tests, researchers found that just 28 got spliced successfully; they also discovered that just a tiny fraction of those possessed the substituted genetic material. According to Huang, for carrying out the process on normal embryos, being close to 100% is an absolute necessity.
He added that failure of achieving that 100% is the only reason why they have decided to stop the study for now. Huang and his team feels that the technique adopted by them is still not mature enough for being tested on human embryos.
What was more concerning was the surprisingly high number of unintentional mutations taking place during the process. The rate was significantly higher than those seen in any other gene-editing experiment carried out previously; these include both studies carried out on mice cells and studies conducted on cells of adult humans.