Dolly Died

[Wardad]

Dolly the Cloned Sheep Dies
By Drog, Section News
Posted on Fri Feb 14th, 2003 at 12:50:40 PM EST

The world's most famous sheep has died. Dolly, who was the first animal to be cloned from an adult cell, was euthanized today. "She had a lung infection and it was quite serious. It is something that happens in sheep," Professor Ian Wilmut, of the Roslin Institute, told Reuters. "She had a detailed veterinary examination and they decided that because she wasn't going to recover. It was kinder to euthanize her. Sheep that are housed are at risk of infection. We housed her because of security and so we could observe her. Unfortunately other sheep who had been in the barn had also had this infection," Wilmut explained, adding that the infection most likely was transmitted from another animal in the barn. "We have to await the results of the post mortem."
Although Dolly's death may not have had anything to do with the fact that she was a clone, she had developed arthritis at an unusually young age, which raised concerns that it was due to a genetic defect caused by the cloning process. Some researchers suspect cloned animals may suffer from premature aging because cloning involves putting genes from a mature animal into an egg. Dolly was created by taking the nucleus out of a cell from the mammary gland of a six-year old ewe and fusing it, using an electrical current, into another sheep egg cell from which the nucleus had been transferred. Dr. Paul Shields and Dr. Ian Wilmut, in a letter to Nature, reported that Dolly's telomeres were 20 percent shorter than those of non-cloned sheep of a similar age. Telomeres are DNA strands at each end of a cell's DNA that become shorter with each cell division. Some scientists have speculated that telomeres are a biological clock that tell cells when it's time to stop dividing and die, but the process has been shown to be more complex in reality. A University of Hawaii experiment, which cloned successive generations of mice partially to test the premature aging theory, encountered no signs of premature aging until the fifth generation of clones. Dolly became a mother in April 1998 when she gave birth to her first lamb, a female called Bonnie, who has normal telomeres.