http://www.newscientist.com/news/news.jsp?id=ns99993393

Dolly the sheep dies young 

Dolly the sheep, the first mammal to be cloned from an adult cell, was put down on 
Friday afternoon, after developing a progressive lung disease.

Dolly's birth six-and-a-half years' ago caused a sensation around the world. But as 
many sheep live to twice this age, her death will refuel the intense debate over the 
health and life expectancy of cloned animals.

The type of lung disease Dolly developed is most common in older sheep. And in January 
2002, it was revealed that Dolly had developed arthritis prematurely. She was cloned 
using a cell taken from a healthy six-year-old sheep, and was born on 5 July 1996 at 
the Roslin Institute, Edinburgh, Scotland.

The Institute's Harry Griffin says: "Sheep can live to 11 or 12 years of age. A full 
post mortem is being conducted and we will report any significant findings". Following 
the post mortem, Dolly will be donated to the National Museum of Scotland in 
Edinburgh, where she will be stuffed and put on display.

Some cloned mammals, including Dolly, have shorter telomeres than other animals of the 
same age. These are pieces of DNA that protect the ends of chromosomes and research 
has shown that they act as molecular clocks, governing the process of ageing in cells.

There have been contradictory studies on the lifespan of cloned animals. In November 
2001, US cloning company Advanced Cell Technology (ACT) said a detailed investigation 
of 24 calf clones revealed that all were normal. 

But a study of cloned mice conducted in February 2002 by researchers at the National 
Institute of Infectious Diseases in Tokyo, Japan, found that they had a shorter 
lifespan than normal mice.

On 2 February 2003, Australia's first cloned sheep died unexpectedly at the age of two 
years and 10 months. The cause of death is unknown and the carcass was quickly 
cremated, as it was decomposing.

Jim
The debate on cloning continues Maru

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