Scientists at the National Institute of Infectious Diseases in Tokyo have found that cloned mice have shorter life spans than mice conceived naturally.
With Dolly the sheep, the first cloned mammal, suffering from premature arthritis, and previous studies showing that cloned animals tend to be obese and may have higher rates of immune dysfunction, the Japanese study will add to worries about the long-term effects of cloning.
Published online today in Nature Genetics, the work is the first to link cloning with premature death.