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It may sound like the stuff of science fiction but cloning, the method by which scientists create an identical copy of a living being, is now very much a reality.

  Dolly the sheep was the first clone to hit the headlines, after Scottish scientists successfully created a genetically identical copy of the adult sheep.

  Cloning has become the hot topic for the 1990s.

  Some hail cloning as a major scientific breakthrough that could offer great advances in medical research, such as information on drugs and diseases.

  Others warn of possible abuses if the science is not properly regulated.

  Whatever your view, you can find out more about cloning, and the arguments for and against, on a range of related websites.

  Visit A Clone in Sheep's Clothing (http://www.sciam.com/explorations/ 030397clone/030397beards.html) to read Dolly's full story. She is, unlike any other mammal that has ever lived, an identical copy of another and has no father. She is the creation of Ian Wilmut and his colleagues at the Roslin Institute in Edinburgh, Scotland.

  They transferred the nuclei from a sheep's cells into unfertilised eggs. The eggs then contained a complete set of genes, just as if they had been fertilised by sperm.

  The eggs were cultured for a period, before being implanted into a sheep. When the sheep gave birth, the resulting lamb was an exact genetic copy of the sheep that provided the transferred nucleus.

  For further details of this cloning technology, go to: http://www.sciam. com/explorations/030397clone/030397 beardsbox.html.

  A number of other corporate and academic laboratories have been quick to follow Dolly's success.

  At least two United States companies have successfully impregnated cows and pigs using cloned cells. At http://www. sciam.com/explorations/090297clone/ beardsley.html, you can read an article about the potential of cloned livestock and find out why the technique is attracting commercial interest.

  But it's not just sheep and monkeys that are involved in the ethical debate over cloning.

  US scientist Dr Richard Seed recently announced that he will be ready to clone the first human being in the next three months. Surf this Web page (http: //news.bbc.co.uk/hi/english/sci/tech/ newsid-45000/45445.stm) where Dr Seed argues the merits of copying human DNA.

  But his announcement prompted immediate criticism. At http://news.bbc. co.uk/hi/english/sci/tech/newsid 45000/45559.stm, you can hear why some critics, including President Clinton's top adviser on bio-ethics have argued against human cloning.



Cloned sheep 'points way' to disposable people