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Summary
This year, Science names Dolly, a lamb cloned from a single cell of an adult sheep, as its 1997 Breakthrough of the Year. Her creation demonstrated the power of cloning technology, surprising both researchers and the public, and igniting a fierce debate about ethics. Although animals have been cloned before, conventional wisdom had held that adult cells cannot give rise to new, mature organisms. The implications of the new technology could open new avenues of research in cancer, development, and even aging, for although Dolly is now 18 months old, her DNA, taken from the donor cell, may be almost 8 years old.