UK researchers have been given the go-ahead to create an embryo that will contain DNA from three people, after the Human Fertilisation and Embryology Authority (HFEA) reversed its decision to ban the procedure.
The technique in question could eventually be used to prevent a series of genetic disorders, known collectively as mitochondrial myopathy, which include muscular dystrophy. These are triggered by defective genes in a woman's mitochondrial DNA. The researchers want to try to prevent these genes being passed on.
Mitochondrial DNA, which is only inherited from the mother, exists in the area around the nucleus of an egg, not in the nucleus itself. It is responsible for the energy management systems in a human being, rather than physical characteristics like hair colour or facial features.
The researchers, led by Professor Doug Turnbull, propose transplanting the fertilised nucleus of an egg that contains faulty mitochondrial DNA into a healthy egg from a donor, leaving the defective mitochondrial genes behind.
The work would be purely lab-based, to find out if the procedure can be carried out safely. Researchers would not be allowed to let the embryo develop into a child.
This, however, has merely added to the controversy surrounding the decision, which has been criticised by pro-life campaigners. Josephine Quintavalle, of Comment on Reproductive Ethics, told The Guardian: "The HFEA are turning this country into the wild west. Wherever they see a law they jump over it. Babies don't need two mothers."
Meanwhile, the Muscular Dystrophy Campaign has welcomed the ruling, saying it is delighted that the research is going to go ahead.
UK law specifically forbids altering the DNA of any cell within an embryo. However, Newcastle University researchers were able to demonstrate that the phrase "altering the genetic structure" has no precise scientific meaning, and argue that the transplant procedure they propose does not actually change an embryo's genetic structure.
Professor Turnbull has been widely quoted as saying that using a third party's mitochondrial DNA is akin to changing the batteries in a faulty radio. The character and nature of the radio remain the same, it would just have a new power source, he argues. ®