British scientists plan work on human-rabbit embryos

[Rajiv]

BRITISH scientists are planning to create embryos that are part-human and part-rabbit to use in investigating treatments for motor neuron disease.
The hybrid embryos would be used to make stem cells for studying the wasting condition that killed the actor David Niven and the former England football manager Don Revie, under proposals from a team that includes the scientist who cloned Dolly the sheep. Although the group, led by Ian Wilmut, of the University of Edinburgh, and Chris Shaw, of King’s College, London, has a licence to clone human embyros for this research, it has been held back by a shortage of the human eggs without which cloning is impossible.
NI_MPU('middle');To get around this, the researchers want to merge DNA from the adult cells of motor neuron disease patients with rabbit eggs, to produce “chimera” embryos that would provide stem cells that are good genetic models of the disease. The chimeric cells would not be capable of giving rise to living animals, it would be illegal to implant them into a womb and they would not be used as a source of cells for transplant therapies. However, as all but a tiny proportion of their genetic material would come from patients, they would be suitable for investigating how the disease progresses and how it might be treated.
Similar experiments have taken place in China, where a team led by Huizhen Sheng, of the Shanghai Second Medical University, has produced more than 100 embryos and several lines of stem cells in this way.
Professor Shaw said yesterday that his group had begun discussions on the proposed work with the Human Fertilisation and Embryology Authority (HFEA), even though it was not clear that it would need a licence. Although the HFEA regulates the creation of embryos, cloning and mixing of human sperm and eggs with those of animals, there are no formal restrictions on introducing human DNA into unfertilised animal eggs.
The HFEA said it considered that such work would need a licence, though it has previously allowed a team at Cambridge University to put the nuclei of human white blood cells into frog eggs without one. The Government is reviewing embryo research and fertility legislation, which was framed in 1990, and is expected to issue more explicit guidelines on the creation of such chimeras.
Professor Shaw said that the chimeras had great potential. “We desperately need an alternative source of eggs if we are going to make progress, and we’re looking at animals,” he said. “Cell lines generated with rabbit eggs may be just as informative as those cloned from patients. If we can derive even just five, we will have a powerful tool for studying motor neuron disease.”