"UK scientists have been given the go-ahead by the fertility regulator to genetically modify human embryos," BBC News reports.
The UK body that regulates research into embryos – the Human Fertilisation and Embryology Authority (HFEA) – has given a licence to Dr Kathy Niakan for her research on stem cells at The Francis Crick Institute in London.
The licence provides permission for genome editing techniques to be used on donated embryos for up to 14 days.
The UK is the first country in the world to make this type of research legal. It remains illegal to implant modified embryos in women.
What is genome editing?
Genome editing uses a range of molecular techniques to make changes to the genome – the complete set of DNA – of individual organisms.
Genome editing can:
- modify genetic information to create new characteristics
- remove regions from genomes – for example, those that can cause genetic diseases
- add genes from other organisms to specific locations within a genome
The editing process modifies the actual nucleotides – the "letters" of DNA (A, T, C, G) – of genetic code.
Dr Niakan plans to use a genome-editing technique called CRISPR-Cas 9, which has become increasingly popular as it is powerful, reliable, quick and relatively inexpensive.
CRISPR-Cas9 uses a combination of the Cas9 protein and a strand of RNA to make breaks in strands of DNA. New genetic code can then be placed inside the breaks, which can allow genetic code to be rewritten.
What type of research has the HFEA licensed?
Dr Niakan wants to investigate how embryos develop in the first few days after conception.
She wants to see what effects certain genome-modifying techniques – effectively turning some genes "on and off" – has on the development of the embryo.
Learning more about the early days of embryonic development may help improve the success rates of fertility treatments like in vitro fertilisation (IVF). It could also lead to new treatments for women who have a history of recurrent miscarriages.
Are there any other potential applications for this technique?
The range of possible applications is huge. Genome editing has already been successfully used in the treatment of one-year-old Layla Richards, who developed acute lymphoblastic leukaemia when she was five months old.
Layla failed to respond to conventional treatment, so staff at Great Ormond Street Hospital asked permission to try a more radical approach, which her parents were happy to give.
In Layla's case, proteins known as transcription activator-like effector nucleases (TALENs) were used as a kind of "molecular scissors" to modify the DNA inside a batch of donated T-cells (an immune cell).
The T-cells were modified to seek out and destroy the abnormal leukaemia cells, while also becoming resistant to the chemotherapy drugs Layla was taking. Layla responded well to the treatment and is now back home with her family.
It could be possible to remove these mutations from an affected embryo and then implant the modified embryo in the mother. However, this type of research is currently illegal.
Have any concerns been raised about HFEA's announcement?
It's fair to say the news has caused controversy in some quarters.
Anne Scanlan, education director of the pro-life charity LIFE, released a statement saying: "We do not know what long-term side effects the tampering with some strands of DNA could have on other strands.
"However, once genetic changes have been made they will be irreversible and handed down to future generations."
And Dr David King, director of the watchdog group Human Genetics Alert, is widely quoted in the media as saying: "This is the first step in a well mapped-out process leading to GM [genetically modified] babies, and a future of consumer eugenics."
Advocates of genome editing have attempted to counter these arguments by making the case that the potential benefits of this technology far outweigh any risk.
Professor Darren Griffin, professor of genetics at the University of Kent, said: "The ruling by the HFEA is a triumph for common sense.
"While it is certain that the prospect of gene editing in human embryos raised a series of ethical issues and challenges, the problem has been dealt with in a balanced manner. It is clear that the potential benefits of the work proposed far outweigh the foreseen risks."