An Introduction to Genetic Engineering

In Chapter 17, the topic of organismal cloning is described, noting the difference between reproductive and therapeutic cloning. Preformationism and epigenesis (as concepts of development), and the work in the early 1900s that led to the development of the concept of nuclear totipotency, are outlined. As the concept was refined, cells that are pluripotent, multipotent or irreversibly differentiated were described. Cloning using nuclear transfer was first proposed in 1938, and achieved in 1952. More correctly known as somatic cell nuclear transfer (SCNT), the birth of Dolly in 1996 was a milestone in that she was the first mammal to be cloned using a fully differentiated somatic cell as the source of the donor nucleus.