Baby born with DNA from 3 people
12 April 2019
Yesterday a clinic in Greece announced that a mother they had treated had given birth to a baby created using the DNA of three people through mitochondrial replacement therapy (MRT). MRT involves creating eggs using the mother's nuclear genetic material (the genes that make you who you are) and healthy donated mitochondria being this is then fertilised with sperm and then implanted.
MRT means that some, or all, of the future baby’s mitochondrial DNA comes from a third party. Mitochondrial DNA is unique in that it is strictly inherited from the mother only. Mitochondrial DNA is only a small part of your DNA (0.1%) and exists in the organelles responsible for producing energy. The treatment is primarily used in cases where the mother has genetic defects which will be passed through her mitochondrial DNA. Crucially MRT can allow a mother with a mitochondrial genetic defect to have a healthy baby which is over 99% genetically matched to her and her partner (or sperm donor).
In this case the method of MRT used was spindle transfer which meant that the mother's nuclear genetic material was removed from her egg and placed into a donor egg which had had it's nuclear DNA removed but retained the healthy mitochondrial DNA. The egg was then fertilised with sperm to create an embryo.
MRT is a very controversial topic raising many ethical, moral and legal issues which have seen it completely banned in some countries. In most other countries it is heavily regulated and only used where there is a medical reason. In 2015 the UK parliament made the decision to legalise mitochondrial donation for use in treatment.