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A clone in sheep's clothing

By Matthew Knight for CNN
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(CNN) -- "Viable offspring derived from fetal and adult mammalian cells" wasn't the catchiest of titles for a scientific paper.

But its publication in the science journal Nature on February 27, 1997 created headlines around the globe and gave us the world's first, and probably last, superstar sheep.

Unveiled to the world's press by Ian Wilmut and colleagues at the Roslin Institute in Midlothian, Scotland on February 22, 1997, Dolly the Sheep was the first mammal to be successfully cloned from an adult cell. She was actually born a few months earlier on July 5, 1996.

Previously, cloning had only been achieved by using embryo cells, but Dolly was created by taking a cell from a six year-old Finn Dorset ewe.

Using a technique called somatic cell nuclear transfer, the team at the Roslin Institute extracted the genetic information from the cell, cultivated it in a laboratory and then placed it in an unfertilized egg, which was then implanted into a surrogate mother.

Originally codenamed 6LL3, the sheep was christened Dolly, after country-singing legend Dolly Parton, on account of the cloned cell having been extracted from the mammary glands of the donor.

Dolly's birth was hailed as a great medical breakthrough but her existence also raised ethical dilemmas about the next obvious step -- the possibility of cloning humans.

Public arguments raged in the following months. The post-Dolly silly season often stretched the bounds of the imagination and taste.

Some newspapers reported that headless human clone factories could soon be used to grow organs and tissues for transplant. Another story claimed that a group of women, who'd undergone abortions, had deep-frozen their fetuses in the hope that they could clone them in future years.

The success and celebrity of Dolly gave rise to an assumption that humans could and would be cloned in a matter of months or years. But progress, as the intervening years have shown, have been far less sensationalist.

By 1999 all was not well with Dolly, who it was thought might be susceptible to premature aging. In January 2002, aged five, she developed arthritis and just over a year later she died from Jaagsiekte disease -- a lung tumor brought on by a virus -- which is common in older sheep. The Roslin Institute, however, stated that there was no evidence to suggest that cloning was a factor in Dolly's demise.

There are still, however, successful results in adult animal cloning -- pigs, dogs, bulls, horses. Some scientists believe that cloning might provide for the world's increasing food demands (the US Food and Drug Administration recently announced that meat and milk from cloned animals was fit for human consumption), or preserve endangered species like the giant panda. It has even been suggested that scientists might, in the future, be able to revive extinct species.

But because cloning animals is a much more a miss than hit affair -- 98 per cent of attempts resulting in death before or just after birth -- it remains an expensive business.

Today, the ethical and religious debates focus on research into human embryo cloning and stem cell research. Dolly creator Ian Wilmut is a vocal supporter of this new research, saying that it would be "immoral" not to seek cures for degenerative conditions such as motor neurone disease and other inherited disorders.

Perhaps far into the future, groups of school children will file past the stuffed remains of an unremarkable sheep at the National Museum of Scotland, unaware that they are the direct beneficiaries of the science that started with Dolly. Scientists may well be on course to create their own immaculate conception.


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Dolly unwittingly became the world's first superstar sheep.

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