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Posted on Nov 22, 2002, 9 a.m.
By Bill Freeman
Yet more doubts about the safety of reproductive cloning have been voiced after Dr. Atsuo Ogura and his colleagues from the National Institute of Infectious Diseases in Tokyo found that cloned mice have significantly shorter lifespans than normal mice. Their study revealed that cloned mice began to die just 300-days after they had been born, and by 800 days more than 83% of them had died.
Yet more doubts about the safety of reproductive cloning have been voiced after Dr. Atsuo Ogura and his colleagues from the National Institute of Infectious Diseases in Tokyo found that cloned mice have significantly shorter lifespans than normal mice. Their study revealed that cloned mice began to die just 300-days after they had been born, and by 800 days more than 83% of them had died. However, in the same time period just 14% of the naturally bred animals died. Furthermore, Ogura found evidence of extensive liver damage, severe pneumonia, and cancer in several of the cloned mice that died.
Previous cloning experiments have revealed that the cloned animals have shortened telomeres, which essentially means that cells are biologically "older" than their chronological age, and thus may age faster. This could translate to a shorter-than-normal lifespan, although this is yet to be proven. However, according to Ogura shortened telomeres did not appear to be the problem in his study. Instead, he says that the study findings suggest that "unexpected" conditions such as organ dysfunction could be shortening the animals lives'.
Dr Davor Solter of the Max-Planck Institute of Immunobiology in Germany, said of the findings: "The relevance to reproductive cloning is obvious, and this paper provides further evidence--if [it] was needed--that any attempt to clone humans would be really irresponsible."
SOURCE/REFERENCE: Nature Genetics (Advance Online Publication) 2002, February 11; 10 1038/ng841
