The 2012 Nobel Prize for Physiology or Medicine was awarded Monday to Sir John B. Gurdon and Shinya Yamanaka for work that revolutionized the understanding of how cells and organisms develop, CNN reports. The Nobel Assembly’s announcement at the Karolinska Institute in Stockholm is the first for what will be a series of prizes announced this week. The Norwegian Nobel committee will announce the most anticipated of the annual honors – the Nobel Peace Prize – on Friday in Oslo. Gurdon, 79, of Dippenhall, England, and Yamanaka, 50, of Osaka, Japan, share the prize jointly “for the discovery that mature cells can be reprogrammed to become pluripotent” — the ability of a cell to differentiate into another cell type, according to the Nobel committee. Gurdon discovered in 1962 that the cells are reversible in an experiment with an egg cell of a frog. Yamanaka discovered 40 years later that mature cells in mice could be reprogrammed as immature cells, the committee said.