Human-Sheep Chimeras

Scientists at the University of Nevada have created a human-sheep chimera by injecting human cells into a sheep foetus. The idea is to eventually create organs suitable for transplant into humans. About 15% of the cells are human.

But the development is likely to revive criticisms about scientists playing God, with the possibility of silent viruses, which are harmless in animals, being introduced into the human race.

Dr Patrick Dixon, an international lecturer on biological trends, warned: "Many silent viruses could create a biological nightmare in humans. Mutant animal viruses are a real threat, as we have seen with HIV."

Animal rights activists fear that if the cells get mixed together, they could end up with cellular fusion, creating a hybrid which would have the features and characteristics of both man and sheep. But Prof Zanjani said: "Transplanting the cells into foetal sheep at this early stage does not result in fusion at all."

Dr. Moreau was unavailable for comment. (And yes, I know this process won't result in anything like the accompanying photo).