Dolly the sheep
Cloning of Dolly the sheep
1. Cells were removed from the udder of a Finn-Dorset ewe.
2. The cells were placed in a medium containing low levels of essential nutrients causing them to starve. This resulted in failure to divide as well as switching off of genes.
3. An unfertilized egg was removed from the uterus of a Scottish Blackface ewe.
4. The two cells were allowed to fuse. The resulting embryo was introduced into another Scottish Blackface ewe. She gave birth to a Finn-Dorset who was an identical “twin” to a sheep six years older.