by Kahleah du Toit, and Maria Dobroskok
Dolly The Sheep
Frozen Mice, and Somatic Cell Nuclear Transfer
Since Dolly the sheep, reproductive cloning has continued to advance; nearly 20 different species have now been cloned. For example, scientists have produced 581 mice from an original donor mouse through 25 rounds of cloning. There were no abnormalities with the mice, even after repeated cloning. In 2008, Wakayama's team created clones from the bodies of mice that had been frozen for 16 years! To clone these animals, researchers use what’s called a somatic cell nuclear transfer.
• Extract an egg from a donor animal (donor A)
• Remove the nucleus -- which contains the genetic material (DNA) from the egg
• Insert a different animal's DNA into that egg (donor B)
• Implant that egg into a surrogate animal for development