Fig. 2.

Stem cell research: key dates. Genetic reprogramming started as early as 1958 with the first somatic nuclear cell transfer, demonstrating that the nucleus was responsible for the function of a cell. The derivation of the first embryonic stem cell from mice was only achieved in the early 1980s. The major breakthrough that turned world attention toward cloning and genetic manipulation happened in 1997 with the first animal cloning of the famous sheep Dolly. Soon after, in 1998, the first human embryonic stem cell was derived. Those cells remained the only pluripotent stem cells at the disposal of researchers until 2006, when Shinya Yamanaka identified the reprogramming factors capable of inducing pluripotency in adult cells. Somatic nuclear cell transfer image is courtesy of Howard Hughes Medical Institute (HHMI). Mouse ESC image is courtesy of emouseatlas.org. Dolly the sheep, human ESC, and mouse iPSC images are courtesy of wikipedia.org. ESC embryonic stem cell, iPSC induced pluripotent stem cell