Dolly (sheep)
Dolly, the first mammal cloned from an adult cell, is born
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Original prompt & settings (JSON) ↗For more than seven months, one of biology's most consequential animals lived at the Roslin Institute without the public knowing she existed.
5 July 1996: a white-faced lamb from a black-faced ewe
At the Roslin Institute in Midlothian on 5 July 1996, a Scottish Blackface surrogate ewe gave birth to a white-faced Finn Dorset lamb, first identified as 6LL and later named Dolly. Her white face immediately distinguished her from the ewe that had carried her.
She had developed from a cultured mammary-gland cell taken from a six-year-old adult Finn Dorset ewe, combined with an enucleated egg supplied by a Scottish Blackface ewe. The live birth demonstrated that genetic material from an adult mammalian cell could be reprogrammed to direct development to term.
One lamb out of 277 reconstructions
The adult mammary-cell series started from 277 reconstructed eggs. Twenty-nine of them reached the morula or blastocyst stage and were transferred to 13 recipient ewes.
One live lamb resulted. Dolly was not the first cloned mammal — earlier sheep had been cloned from embryonic cells — and her distinction was the adult-cell origin.
Seven months of silence
The achievement stayed confidential that day and for long after. Roslin kept observing her while preparing genetic evidence and a paper, and announced her publicly on 22 February 1997, days before the research paper appeared on 27 February.
In the week after the announcement, Roslin received 3,000 telephone calls. The name was a mammary-gland joke: the team chose Dolly after the singer Dolly Parton.
Sources
Researched 23 Aug 2026 5 sources 2 audit passes
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What the sources leave uncertain
- The birth date and location are directly documented by Roslin and are not disputed.
- Calling the three contributing ewes 'mothers' is useful shorthand but biologically imprecise: the mammary-cell donor supplied nearly all nuclear DNA, the egg donor supplied the cytoplasm and mitochondrial DNA, and the surrogate supplied the womb.
- The original donor material was a cultured mammary-cell population. Dolly is securely described as cloned from an adult cell, although early scientific discussion noted that the exact differentiated cell type within that population could not be identified retrospectively.