Human embryos edited for first time by Chinese scientists

23 Apr 2015

It has been confirmed that scientists in China have been editing the genomes of human embryos as one team has published a paper detailing its findings on attempts to fix faulty genes.

The first indication that Chinese scientists had possibly been working with human embryos arose last month in Nature with a significant proportion of the scientific community calling for a moratorium on any human embryo research when it comes to the editing of genes, with four scientists calling for an outright ban on any human embryo research.

Now, however, the first confirmation of this research has surfaced following the publication of a paper in Protein & Cell from a team based in the city of Guangzhou that used genes from within the embryos that are responsible for a serious blood disorder known as beta thalassaemia, with the help of a gene-editing technique known as CRISPR/Cas9.

In theory, when the CRISPR enzyme complex is inserted into the DNA it can be programmed to target a faulty gene and immediately replace it with a healthy gene and, while it has been tested for a number of years on animals, this marked the first time it had been used on human embryos.

‘We still think it’s too immature’

Knowing the controversy this testing would cause, the Chinese team has come out defending its use of embryos by stating that they were ‘non-viable’ embryos that scientifically could not become human children, which were obtained from fertility clinics.

Judging by the findings of the team, which was led by Junjiu Huang, a gene-function researcher at Sun Yat-sen University in Guangzhou, we are still a long way off from one day being able to replace faulty genes with healthy ones given that, from the 86 embryos tested, only 28 were successfully spliced with the healthy gene and, as a result, the testing has now stopped.

“If you want to do it in normal embryos, you need to be close to 100pc,” Huang said when commenting in Nature. “That’s why we stopped. We still think it’s too immature.”

Adding his worries about testing on human embryos in any capacity, George Daley, a stem cell biologist at Harvard Medical School in Boston, said: “Their study should be a stern warning to any practitioner who thinks the technology is ready for testing to eradicate disease genes.”

Until it can be perfected, Huang has said that he will return to testing on adult human and animal genomes.

Human DNA image via Shutterstock

Colm Gorey was a senior journalist with Silicon Republic