This July 5 marks the 27th anniversary of the birth of Dolly the sheep. She was the first cloned animal, which was an unprecedented event in science. Her birth, in 1996, was not announced until seven months later.
Who were its creators? Scientists at the Roslin Institute in Edinburgh, Scotland, Ian Wilmut and Keith Campbell. Dolly was actually a sheep resulting from a nuclear combination. It was made from a donor cell differentiated to an unfertilized, anucleated (no nucleus) egg.
Unique among many
Until that time it was believed that clones could only be obtained from one embryonic cell. But five months later Dolly was born. She was the only lamb resulting from 277 fusions of anucleated eggs with mammary cell nuclei.
Dolly lived forever at the Roslin Institute. There she was crossed with a Welsh Mountain male to produce six offspring in total. In the fall of 2001, at the age of five, Dolly developed arthritis and began to walk painfully. She was successfully treated with anti-inflammatory pills.
On February 14, 2003, Dolly was euthanized due to progressive lung disease. Her species has a life expectancy of about 11 to 12 years. However, Dolly lived only six and a half years. Necropsy showed that she had a form of lung cancer called Jaagsiekte. No connection between this premature death and being a clone could be certified.
Famous sheep
However, some have speculated that she was a paraplegic, due to her crooked hooves. There was an aggravating factor to Dolly’s demise and that was that she had a genetic age of six years. This is the same age as the original sheep when she was cloned. One basis for this idea was the finding of her short telomeres, which are usually the result of the aging process. However, the Roslin Institute has established that intensive health checks revealed no abnormalities in Dolly. Nothing could suggest logical reasons for the premature aging of the first cloned animal.
The dissected remains of Dolly the sheep are on display at the Royal Museum of Scotland. Dolly will undoubtedly be celebrated for a long time to come.
