Jessica Hamzelou writes for New Scientist:
A review of technologies that create three-parent embryos to avoid mitochondrial disease has found no evidence that the methods are unsafe, calling for further research. Medical charities have followed up the report with a call to the UK’s health secretary to prepare to regulate the technology in clinics.
A fertilised egg has 98 per cent of its DNA held in its nucleus. Half of this will be from the mother and half from the father. The remaining 2 per cent is what’s known as mitochondrial DNA – DNA in the cells’ “powerhouses” that are found outside of the egg’s nucleus, and are inherited solely from the mother.
Gene mutations in a woman’s mitochondrial DNA can cause mitochondrial disease in her children. The effects can range from mild, almost symptomless disease to serious and often fatal conditions. Researchers are aiming to avoid these serious conditions using donor eggs with mutation-free mitochondria.
There are two techniques that could be used to do this. The first – known as maternal spindle transfer – involves taking the DNA from the nucleus of one woman’s egg and inserting it into an emptied nucleus of another woman’s egg. The egg can then be fertilised with a man’s sperm. A second technique called pronuclear transfer starts by fertilising a woman’s egg with a man’s sperm using IVF. The nucleus of the fertilised egg can then be transferred into an emptied nucleus in another egg in the same way.
In both cases, the resulting fertilised eggs contain DNA from both of their parents in the nucleus along with the donor egg’s mitochondrial DNA…
Article continues at New Scientist.