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Interactives -- DNA

Implications & Ethics : Cloning

In July 1996, Dolly, the world's most famous sheep, was born at the Roslin Institute in Scotland. Dolly was a clone-a genetic replica-and the world's first mammal to be cloned from an adult cell. Dolly was created by a reproductive cloning technology called somatic cell nuclear transfer. Mammary cells from the udder of a 6-year-old Finn Dorset ewe were grown in a lab for a few weeks, then fused with an unfertilized egg from an unrelated ewe that had been stripped of its nuclear genetic material. Two hundred and seventy seven of these reconstructed cells were cultured and induced to begin cell division, just like normal embryos. When they reached a suitable stage, 29 of the embryos were implanted in to surrogate Scottish Blackface ewes. One gave rise to Dolly.

Since Dolly's birth, researchers worldwide have employed the same method used to create her to clone rats, cattle, goats, gaurs, pigs, cats, dogs, horses, deer, rabbits, fruit flies, and a mule. Cloning technology also offers the possibility of resurrecting extinct plant and animal species (a lá the movie Jurassic Park).

Over the past few years, several research groups have claimed to have cloned human beings. One group, Clonaid, the medical branch of a religious sect called the Raëlian Movement, said in 2004 that it had successfully cloned 13 children. The report has not been substantiated.

In 2004, South Korean scientists said that they had grown 30 cloned human embryos to the one-week stage, although much of their research has been revealed to be fraudulent. This type of cloning is distinctive from the reproductive cloning methods used to produce Dolly and other animals. It is considered "therapeutic," or "embryo cloning," undertaken not to produce human beings but for the purpose of producing embryos from which human stem cells can be harvested. Stem cells have the potential to become any kind of cell in the body and offer the potential for curing many types of disease.

These reports and the prospect of future human cloning efforts have raised serious concerns among religious groups, politicians, and ethicists, who worry about misuses of the technology and fear that scientists are "playing God." Most scientists, in fact, object to human reproductive cloning.


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