Illustration of the British geneticist and developmental biologist John Gurdon (born 1933). Gurdon is best known for his work on nuclear transfer. In 1962 he successfully cloned a Xenopus frog by transferring the nucleus from a mature intestinal tadpole cell into an egg cell. This nucleus from a specialised cell was able to drive the development of the egg into an adult frog. This work demonstrated for the first time that a mature cell is able to return to an immature state where it is pluripotent (able to differentiate into any of the cell types of the body). Gurdon was awarded the 2012 Nobel Prize in Physiology or Medicine, along with the Japanese stem cell researcher Shinya Yamanaka, for this work.