The 1996 Roslin Institute cloning experiment produced Dolly, the first mammal cloned from an adult somatic cell.
Scientists led by Ian Wilmut and Keith Campbell used somatic cell nuclear transfer. They removed the nucleus from an unfertilized sheep egg and inserted the nucleus from an adult mammary-gland cell. After electrical stimulation, the reconstructed embryo began dividing and was implanted into a surrogate ewe.
Dolly was born on 5 July 1996 and publicly announced in February 1997. Her birth showed that the nucleus of a differentiated adult cell could be reprogrammed to direct the development of an entire animal. She was genetically almost identical to the nuclear donor, although mitochondrial DNA came from the egg donor.
Dolly was a Finn Dorset sheep, and the surrogate was a Scottish Blackface. She was not the first animal cloned by nuclear transfer, because earlier experiments had cloned frogs and sheep embryos. Her importance came from demonstrating successful cloning using an adult cell nucleus.