Wilmut and Campbell used their revised nuclear transfer technique on unfertilized sheep eggs, which they combined with cells from sheep embryos in a late stage of development. Most of the embryos made from the combined cells died, as the researchers had expected, but a few survived. When these grew large enough, Wilmut and Campbell transplanted them into sheep surrogate mothers. Finally, in July 1995, the Roslin team produced their first cloned animals, two Welsh Mountain ewes (female sheep) that they named Megan and Morag.
Wilmut and Campbell wondered how far they could take their success. Almost as a joke, they decided to see whether they could reprogram a mature cell from an adult animal to make it able to manufacture an entire embryo. PPL Therapeutics, a company founded in 1987 to commercialize Roslin's products, agreed to fund the experiment, hoping that the cloning technique could be used to create duplicates of animals genetically engineered to produce proteins useful in medicine.
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