A knighted British scientist whose work as a young Phd student set the stage for the future of cloning research has been awarded the Nobel Prize for Physiology or Medicine.
Professor Sir John Gurdon, 79, shares the prize with leading stem cell scientist Professor Shinya Yamanaka, from Kyoto University in Japan.
The scientists won the award for their work showing that mature cells can be "reprogrammed" to behave like embryonic cells.
Sir John, who was told while a pupil at Eton College to forget "ridiculous" notions of being a scientist, said he was "immensely honoured" to receive the accolade.
He added: "It is particularly pleasing to see how purely basic research originally aimed at testing the genetic identify of different cell types in the body has turned out to have clear human health prospects."
In the late 1950s, Sir John was working for a Phd in zoology at Oxford University when he made a pivotal discovery that sent shockwaves through the scientific establishment.
He successfully cloned the South African frog Xenopus from a cell taken from the lining of a tadpole's intestine. By transplanting the cell nucleus into an empty Xenopus egg cell, he produced a frog that was genetically identical to the original tadpole.
The results, published in 1962, proved for the first time that the genetic code in the cell nucleus contains all the information needed to create a new organism.
More than four decades later, in 2006, Prof Yamanaka showed how mature cells in mice could be made to revert to a youthful embryonic state.
Like stem cells from embryos, the "induced pluripotent stem cells", or iPSCs, had the potential to develop into any kind of cell in the body.