This post appeared originally on BioEdge by Michael Cook
Two stem cell researchers have shared the Nobel Prize in Medicine for 2012, an elderly Briton, Sir John B. Gurdon, and a younger Japanese, Shinya Yamanaka. By a serendipitous coincidence, Sir John made his discovery in 1962 — the year of Yamanaka’s birth.
In his classic experiment at the University of Cambridge, Sir John discovered that cell development is reversible. The conventional wisdom was that cells could never change once they had specialized as nerve, skin, or muscle cells. He proved that this was wrong by replacing the nucleus of a frog egg cell with a nucleus from a mature intestinal cell. This modified cell developed into a normal tadpole.
This astonishing development eventually led to the cloning of the first mammal, Dolly the sheep, in 1996. But while the technique worked, no one really understood cell development. The obvious target for research was the embryo. From this ball of undifferentiated cells come each of the body’s specialized cells — more than 200 of them in humans. Surely the answer must lie there. In 1998 an American scientist, James Thomson, of the University of Wisconsin-Madison, isolated and cultivated human embryonic stem cells.
But a one-eyed focus on embryos left stem cell science hostage to ethics. Despite scientists’ bravado, everyone had some qualms about destroying embryos for their stem cells. Even Thomson admitted to the New York Times that “if human embryonic stem cell research does not make you at least a little bit uncomfortable, you have not thought about it enough”.