Reports are coming in of UK scientists successfully creating human embryos using the DNA from three people. Doug Turnbull, professor of Neurology at Newcastle University, and his team used the DNA of two women and one man to make ten embryos, said the Daily Telegraph, yesterday, 5th February.
The scientists said the embryos were primarily the product of one man and one woman (the parents), with a donation of mitochondrial DNA from the second woman (the donor). The project is being heralded as a breakthrough in the prevention of inherited diseases that pass from mothers to their children via mitochondrial DNA, which humans only inherit from their mothers.
Mitochondria are inside every cell of the human body and regulate essential cell functions such as metabolism (which provides cells with energy to function) and cell death. Because they have such an important role, when they go wrong they lead to a wide range of human diseases. These include myopathy and muscular dystrophy (muscle weakness and progressive degeneration), a type of diabetes, liver failure, stroke-like events, blindness and deafness, epilepsy, and other neurological disorders.
Pro-life groups are bitterly opposed to the method used by the Newcastle team, said the Daily Telegraph. But others are keen for it to move from the lab to the treatment stage as soon as possible. Lord Walton of Detchant has tabled an amednment to the Human Fertilisation and Embryology Bill that is currently going through parliament, that would allow the treatment to be approved by the Human Fertilisation and Embryology Authority (as opposed to having to seek parliament’s permission), said the paper.
The scientists used 10 severly abnormal fertilized embryos produced for but not used in fertility treatment. They removed the nucleus of the embryos and implanted them in donor eggs stripped of their nuclear but not of their mitochondrial DNA. The embryos developed normally but were destroyed after six days, according to BBC News.
In previous experiments the Newcastle team conducted with mice, the embryos developed normally and the offspring had none of the characteristics of the egg donor, only of the nuclear DNA parents.
The new embryos had the nuclear DNA of their “parents” (one man and one woman), and the mitochondrial DNA of the egg donor (the second woman).
Professor of Neurogenetics at Newcastle, Patrick Chinnery, who also took part in the project, told the Associated Press that:
“We are not trying to alter genes, we’re just trying to swap a small proportion of the bad ones for some good ones.”
“Most of the genes that make you who you are are inside the nucleus,” he said, “we’re not going anywhere near that.”
BBC News said the Newcastle team effectively gave the embryos a “mitochondria transplant”. The only genetic information introduced from the second woman, the egg donor, was in the mitochondrial DNA and not the nuclear DNA. Mitochondrial DNA represents about 16,000 of the 3 billion DNA base pairs in the human genome.
A representative of the Muscular Dystrophy Campaign, Dr Marita Pohlschmidt, told the BBC the Campaign was confident the research would result in badly needed treatment:
“Mitochondrial myopathies are a group of complex and severe diseases,” said Pohlschmidt.
Chinnery said:
“We believe that from this work, and work we have done on other animals that in principle we could develop this technique and offer treatment in the forseeable future that will give families some hope of avoiding passing these diseases to their children.”
The research, which was funded by the Muscular Dystrophy Campaign and has been described as being in the preliminary stage, has not yet been published in a peer reviewed journal, but according to the Daily Telegraph, it was presented to the Medical Research Council Centre for Neuromuscular Diseases in London last week.
Click here for more information on mitochondria and associated research (mitochondrial.net).
Sources: Daily Telegraph, Associated Press, BBC News.
Written by: Catharine Paddock, PhD