London – In a world first, Chinese scientists have altered the genes of human embryos – sparking fears that they are on a slippery slope towards creating ‘designer babies’.
British and US scientists have expressed concerns over the ethics of the experiment, with one doctor calling for the research to be banned.
Editing genetic codes to remove inherited disease has already been shown to work on mice. However most geneticists believe the procedure is not ready to be carried out on human embryos.
The team from Sun Yat-sen University in Guangzhou, south China, were aiming to modify the gene responsible for beta thalassaemia – a potentially fatal inherited blood disorder.
Using an advanced ‘cut and paste’ technique involving the injection of enzymes, they attempted to edit the DNA in 86 ‘non-viable’ human embryos from local fertility clinics. Non-viable embryos are those which cannot result in a live birth.
The genes only changed in 28 cases, but even among those there were numerous mutations which were not intended by the scientists. Many experts said the ultimate failure of the procedure underlines the case for caution with the technique, which is known as CRISPR/Cas9.
Dr David King, from watchdog Human Genetics Alert, said: ‘This news emphasises the need for an immediate global ban on the creation of genetically modified designer babies.
‘It is critical that we avoid a eugenic future. If China does not want to get the reputation of being the wild west of the new eugenics it must join the many countries – including the UK –which would ban such research.Lead scientist Dr Junjiu Huang admitted the experiment, published by journal Protein and Cell, had failed. He told Nature News: ‘If you want to do it in normal embryos, you need to be close to 100 per cent. That’s why we stopped. It’s too immature.’
He added the report was rejected by leading journals Science and Nature. Both organisations last night refused to confirm or deny the claim.
He said: ‘We wanted to show our data to the world so people know what really happened with this model, rather than just talking about what would happen without data.’
Dr George Daley, a stem cell biologist at Harvard Medical School, said the experiment poses a ‘cautionary tale’.
He said: ‘Their study should be a stern warning to any practitioner who thinks the technology is ready for testing.’
Professor Shirley Hodgson, an expert in cancer genetics at St George’s, University of London, said: ‘This is a significant departure from currently accepted research practice. Can we be certain that the embryos were indeed non-viable?
‘The fact that there were a number of “off-target” mutations is clearly a worry.’
While genetic modification of human embryos is illegal in the UK, the historic decision was taken in February to allow ‘three-parent babies’. This legalised the donor replacement of mitochondrial DNA – the so-called batteries which power the body’s cells.
Although the procedure has its critics, it would not alter the genetic characteristics of a child, unlike the Chinese experiment.
Alastair Kent, from Genetic Alliance UK which supports families with genetic conditions, said patients would be interested to hear about the Chinese experiment – but undoubtedly would be aware that ‘ethical challenges will need to be resolved’.
Daily Mail