Winners of Nobel Prize in Physiology or Medicine 2012: John B. Gurdon and Shinya Yamanaka
Each individual develops from a single cell, which is the fertilized egg. During the next few days in the uterus, the egg multiplies into a number of similar cells. As time progresses, the cells get differentiated into specialized tissues. Similar tissues form organs, each of which performs definite functions.
John B. Gurdon and Shinya Yamanaka discovered that the reverse is also possible. Their experiments, separated by a gap of over 40 years, demonstrated that specialized cells can be converted into immature cells, and these immature cells contain the information that can enable them to again form specialized cells and tissues.
In his experiment conducted in 1962, John Gurdon replaced the nucleus of the egg of a frog with a mature nucleus from an intestinal cell of a tadpole. The result - the modified egg cell developed into a tadpole.
Shinya Yamanaka conducted his experiments on mice in 2006 and took Gurdon's work a step further. He introduced a few genes into mature cells and converted the same cells into immature stem cells. These immature cells, called induced pluripotent stem cells (iPS cells), could later develop into mature cells.
These important findings have changed our outlook regarding mature cells and have opened newer avenues for further studies in understanding diseases and developing newer therapies.