Chimera: sheep have 15 per cent human
cells and 85 per cent animal cells. (File Photo) Photo
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BEIJING, March 26 (Xinhuanet) -- Scientists have created the world's first
human-sheep chimera -- which has the body of a sheep and half-human organs,
according to news report Monday.
The sheep have 15 percent human cells and 85 percent
animal cells and their evolution brings the prospect of animal organs being
transplanted into humans one step closer.
Professor Esmail Zanjani, of the University of Nevada, has
spent seven years and about 9.8 million dollars perfecting the technique,
which involves injecting adult human cells into a sheep's foetus.
He has already created a sheep liver which has a large
proportion of human cells and eventually hopes to precisely match a sheep to a
transplant patient, using their own stem cells to create their own flock of
sheep.
The process would involve extracting stem cells from the
donor's bone marrow and injecting them into the peritoneum of a sheep's foetus.
When the lamb is born, two months later, it would have a
liver, heart, lungs and brain that are partly human and available for
transplant.
At present 7,168 patients are waiting for an organ
transplant in Britain alone, and two thirds of them are expected to die before
an organ becomes available.
Scientists at King's College, London, and the North East
Stem Cell Institute in Newcastle have now applied to the HFEA, the Government's
fertility watchdog, for permission to start work on the chimeras.
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.
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."
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