Two scientists whose stem-cell research was separated by over four decades have been announced as the winners of 2012's Nobel Prize in Physiology or Medicine. Sir John B. Gurdon of Cambridge, UK discovered in 1962 that the "specialization" of cells is reversible — in his experiment, he replaced an immature cell nucleus in an egg cell of a frog with a cell that had matured and developed into an intestinal cell. Despite this change, the frog egg cell matured into a normal tadpole, proving that the mature intestinal cell still contained all the relevant DNA necessary to develop all of the tadpole's cells. His findings were a direct challenge to the prevailing wisdom that once a pluripotent stem cell (an immature cell that is capable of developing into all of the cell types in a fully mature organism) matured into a specific cell type, it no longer contained the DNA data that maturation process.

Shinya Yamanaka's research some 44 years later took this concept a step farther in his work with embryonal stem cells — immature (or pluripotent) cells that that were isolated from the embryo and cultured in a laboratory. Yamanaka first found specific genes that that kept these embryonal cells from developing, and then later discovered that the correct combination of genes applied to mature cells would actually reverse the development and return them to the pluripotent state.

The combination of Gurdon and Yamanaka's research has had wide-ranging implications in the medical community — The Wall Street Journal reports that just last week, the scientist behind the cloning of Dolly the sheep used Yamanaka's method to create viable mouse egg cells in a lab. In summing up the impact of this research, the Nobel Prize organization said that scientists now have "new opportunities to study diseases and develop methods for diagnosis and therapy."