Polly

cloned sheep

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July 20, 2026

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Polly was a cloned sheep born in 1997, notable for being genetically engineered to produce a human protein. She was created by scientists at the Roslin Institute in Scotland, the same team that cloned Dolly, the first adult mammal.12

Polly was produced using somatic cell nuclear transfer (SCNT), a technique where the nucleus from an adult cell is transferred into an enucleated egg cell. The nucleus used for Polly came from a fetal fibroblast cell that had been genetically modified to express the human gene FIX. This gene encodes human factor IX, a clotting protein absent in individuals with hemophilia.321

The successful cloning of Polly represented an advancement in "pharming," the production of therapeutic proteins in animals. While Dolly proved that adult cells could be used for cloning, Polly demonstrated the potential for genetically engineering cloned animals for medical purposes.21

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pharming
…generated another pharmed sheep named Polly, a Poll Dorset clone made from nuclear transfer using a fetal fibroblast nucleus genetically engineered to express a human gene known as FIX. This gene encodes a substance called human factor IX, a clotting factor that occurs naturally in most people but that is…
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…generated another pharmed sheep named Polly, a Poll Dorset clone made from nuclear transfer using a fetal fibroblast nucleus genetically engineered to express a human gene known as FIX. This gene encodes a substance called human factor IX, a clotting factor that occurs naturally in most people but that is…
Read More

Ian Wilmut
Dolly and Polly
…Wilmut and his colleagues generated Polly, a Poll Dorset clone made from nuclear transfer using a fetal fibroblast nucleus genetically engineered to express a human gene known as FIX. This gene encodes a substance called human factor IX, a clotting factor that occurs naturally in most people but is absent…
Read More
…Wilmut and his colleagues generated Polly, a Poll Dorset clone made from nuclear transfer using a fetal fibroblast nucleus genetically engineered to express a human gene known as FIX. This gene encodes a substance called human factor IX, a clotting factor that occurs naturally in most people but is absent…
Read More