A clone is a living being whose genes are identical to those of another. In 1997, Scottish scientists worked at the Roslin Institute, Edinburgh, under the direction of the doctor Ian Wilmut, and succeeded for the first time created by cloning a living: Dolly the sheep. This team of scientists removed a cell from the udder of the mother of Dolly. He dismissed the cytoplasm of the cell and kept the core where the chromosomes that carry the genetic codes. Then the same animal took an unfertilized egg. Dispensed with its nucleus and cytoplasm was used that contains nutrients for the developing fetus. He combined the core of the udder with the egg's cytoplasm, and thus obtained cell electric shock was applied to divide as if it had been fertilized. At eight weeks the embryo is implanted in the uterus of the mother. Three weeks later, Dolly was born.
The sheep Dolly was named in tribute to Dolly Parton, favorite actress of Ian Wilmut.
The technique of cloning was created in 1967 by John Gurdon, who won the Nobel Prize for his research in this area.
Cloning opens a vast scope for improvement of livestock but as I said Wilmut himself is ethically unacceptable in the case of man.