As far back as 1962 Gurdon became the first scientist to clone an animal, making a healthy tadpole from the egg of a frog with DNA from another tadpole's intestinal cell. That showed that developed cells carry the information to make every cell in the body - decades before other scientists made world headlines by cloning the first mammal from adult DNA, Dolly the sheep.
More than 40 years later, Yamanaka produced mouse stem cells from adult mouse skin cells by inserting a small number of genes. His breakthrough effectively showed that the development that takes place in adult tissue could be reversed, turning adult tissue back into cells that behave like embryos.
Stem cells created from adult tissue are known as "induced pluripotency stem cells", or iPS cells. Because patients may one day be treated with stem cells from their own tissue, their bodies might be less likely to reject them.
"The eventual aim is to provide replacement cells of all kinds," Gurdon's institute explains on its website.
"We would like to be able to find a way of obtaining spare heart or brain cells from skin or blood cells. The important point is that the replacement cells need to be from the same individual, to avoid problems of rejection and hence of the need for immunosuppression."
MY COMMENT: The implication of this technology is that the ethical squeamishness of using embryonic stem cells is mitigated, and, in fact, autologous donor cells (same person) also obviates the need for immunosuppression and therefore may be superior in practice.