FOR opponents of embryo experiments, it has been a fraught week. First came permission for a British team to produce 鈥渢hree-parent鈥� embryos. A day later came news that 鈥渧irgin conception鈥� embryos had been created from single, unfertilised human eggs.
On 8 September, the UK鈥檚 Human Fertilisation and Embryology Authority, which regulates embryo research, gave its consent to a team at the University of Newcastle upon Tyne to create three-parent embryos for research. The aim is to tackle inherited metabolic diseases resulting from faulty DNA in mitochondria. These cell components are passed on from mother to offspring, so the idea is to replace faulty mtDNA in a fertilised egg with healthy mtDNA from the fertilised egg of a second woman 鈥� the third 鈥減arent鈥�.
The HFEA decision came close to breaking a law forbidding replacement of the nucleus of a human embryo. The Newcastle team successfully argued that, at the time of replacement, the embryos would not contain true nuclei, but so-called pronuclei. These comprise two 鈥渉alf nuclei鈥� supplied by the mother and father that have yet to merge.
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鈥淭his came close to breaking a law forbidding replacement of the nucleus of an embryo鈥�
A day later, Paul de Sousa of the Roslin Institute in Edinburgh announced that he had produced six 鈥減arthenogenetic鈥� human embryos by coaxing single eggs into multiplying without fertilisation. His aim is to mine these for embryonic stem cells.
