Follow the link to read more (http://www.nobelprize.org/nobel_prizes/medicine/laureates/2012/)
In 1962, John Gurdon of Cambridge University showed that a new tadpole could be created by taking the genetic information (nucleus) from the intestine cell of an adult frog and implanting it into an unfertilized frog egg. This led him to conclude that the intestine cell contains all the genetic information need to create a whole new frog, and that the process of specialization in cell development is reversible. It was the first time in the world that this has been achieved and was considered no more than a scientific curiosity for many years. However, this discovery would eventually lead to a technology called somatic cell nuclear transfer (SCNT), and is responsible for Dolly the sheep.
Over forty years later in 2006 Shinya Yamanaka of Kyoto University showed in a series of experiments on mice that adult mouse cells could be reprogrammed into stem cells by modifying the genetic information (gene) in those cells. Rather than transferring the genetic information into an egg, like Gurdon, he altered the existing information in an adult cell, essentially reprogramming the cell. These stem cells are known as induced pluripotent stem cells (iPS) and are an extremely important area of stem cell research.
International Stem Cell Corporation (ISCO) does not use either of these techniques, as both methods pose problems when the treatment of human diseases is the goal. SCNT because it is essentially cloning which is immoral as well as illegal, and iPS because it involves considerable reprogramming of the cell's genes, leading to serious safety concerns. ISCO uses a third method called parthenogenesis, which stimulates unfertilized human eggs chemically allowing them to start dividing. The stem cells derived in this way are similar to embryonic stem cells, but avoid the ethical controversy associated with the destruction of a viable human embryo. ISCO is using these stem cells to develop treatments for Parkinson’s disease, inherited metabolic liver diseases and corneal blindness.