Latest research shows cloned mice die young
Scientists in Tokyo, Japan, have thrown fresh doubt on the safety of cloning with an experiment showing that cloned mice die younger than their naturally born counterparts. Researchers at Tokyo's National institute of infectious diseases found that ten out of their twelve mice clones died prematurely. The rodents suffered pneumonia, liver failure and tumours. The Japanese findings have led to fresh doubts about the dangers of cloning mammals by highlighting the first possible link between cloning and early death. The team that carried out the research said their results raised new concerns about attempts to create human clones through reproductive cloning. The scientists said the immune systems of the mice may have been damaged by the cloning process. However, they did not rule out other factors such as the genetic make up of the mice and the cell type used to clone them. The scientists, writing in the journal Nature Genetics, said: 'The possible negative long term effects of cloning, as well as the high incidence of spontaneous abortion and abnormal birth of cloned animals, give cause for concern about attempts to clone humans for reproductive purposes.' The new research follows the revelation that Dolly the sheep, created using cell nuclear transfer at the Roslin Institute in Scotland in 1996, is suffering from arthritis at just five years old. Following the discovery, Professor Ian Wilmut, one of the scientists who created Dolly, called for further research into the health of cloned animals. Discussing the implications of the mouse study, Dr Harry Griffin, also from the Roslin Institute, is reported to have said: 'No doubt if Dolly dies before her duly allotted time, it will be put down to premature ageing...But you can't conclude anything from a single mammal.'