Cloning research hits setbackCloning research hits setback|
Technology called unsafe as mice in experiment get tumours, obesity BY LOIS ROGERS LONDON- Cloned mice are mysteriously developing tumours and obesity in an unexpected setback to the development of the new technology. The observation has provided fresh evidence that "reprogramming" cells to grow into perfect replica individuals can produce unforeseen consequences. Other cloned animals have shown excessive growth patterns in the womb, meaning they are too big to be born or have died soon after birth. There have also been reports of heart disease and abnormal liver and lung development in cloned animals worldwide. Data from the University of Hawaii, where the first mouse was cloned more than two years ago, indicate the onset of obesity in adulthood is linked to events in the earliest moments of embryonic life. More than 200 cloned mice have been created. In some strains all the identical mice have become large, while in others some have developed obesity while their cloned siblings have remained a normal size. Dr. Randall Sakai, a geneticist from the University of Cincinnati drafted to help solve the puzzle, said: "All we know is that the process of cloning produces an animal that grows normally, but becomes a lot larger. "We are trying to find out if any of the brain neurochemicals have been modified in the cloning process." Details will be published shortly. Tony Perry, a British-born scientist now at Rockefeller University in New York, with Teruhiko Wakayama, the mouse-cloning pioneer, said: 'We are still working out whether clones are normal or, if abnormal, in what way." Perry said the growing evidence of problems in clones was a warning of the risks of using them as potential donors for organs such as hearts, livers and kidneys for human transplant, or as a source of brain cells to transplant into human sufferers of degenerative conditions such as Parkinson's disease. Last week Cumulina , the first mouse to be produced from an adult cell died of old age. However, it was revealed she had earlier undergone surgery to remove skin tumours. A number of other clones are believed to be similarly affected. Other work by French researchers last year produced evidence that a cow cloned from ear cells had lethal blood and heart defects. The right chamber of one clone's heart was abnormal, and red and white blood cell numbers inexplicably plummeted after birth. The clone died from severe anemia after 51 days. Scientists at Kinki University in Japan cloned eight cows two years ago. Four died soon after birth from infections, but all had appeared normal. Harry Griffin, assistant director of the Roslin Institute in Edinburgh which produced Dolly the cloned sheep, said: "All the research groups that cloned animals in the first wave have gone out of their way to emphasize that this technology is new and unsafe." LONDON SUNDAY TIMES |
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