Two scientists shared the 2012 Nobel Prize in Physiology or Medicine, announced the Nobel Assembly at Swedish Karolinska Institute in Stockholm on Monday.

"The Nobel Assembly at Karolinska Institutet has today decided to award the Nobel Prize in Physiology or Medicine 2012 jointly to John B. Gurdon and Shinya Yamanaka for the discovery that mature cells can be reprogrammed to become pluripotent," said Goran Hansson, Director of the Nobel Assembly at Swedish Karolinska Institute.

"Their findings have revolutionized our understanding of how cells and organisms develop," the assembly said in a statement.

Gurdon challenged the dogma that the specialized cell is irreversibly committed to its fate and made a landmark discovery in 1962 that the specialization of cells is reversible in an experiment with an egg cell of a frog.

Yamanaka discovered in 2006 how intact mature cells in mice could be reprogrammed to become immature stem cells.

"These groundbreaking discoveries have completely changed our view of the development and cellular specialization. We now understand that the mature cell does not have to be confined forever to its specialized state," the statement said.

The juries commented that textbooks have been rewritten and new research fields have been established.

"By reprogramming human cells, scientists have created new opportunities to study diseases and develop methods for diagnosis and therapy," said the statement.

It gives an example that skin cells can be obtained from patients with various diseases, reprogrammed and examined in the laboratory to determine how they differ from cells of healthy people, thus provide new opportunities to develop medical therapies, the statement added.

Born in Britain in 1933, Gurdon graduated from the University of Oxford in 1960 and became a professor of Cell Biology after 1972. He is currently at the Gurdon Institute at the University of Cambridge.

Yamanaka was born in Japan in 1962 and got his PhD at Osaka University. He is professor at Kyoto University and is also affiliated with the Gladstone Institute in San Francisco, the United States.

The winners of the physics prize will be announced on Tuesday, to be followed by those for chemistry on Wednesday, literature on Thursday, peace on Friday and economics next Monday.

The annual Nobel Prizes are usually announced in October and are handed out on Dec. 10, the anniversary of the 1896 death of Alfred Nobel, a Swedish industrialist and the inventor of dynamite.

The prizes have been awarded since 1901. A number of 853 persons or organizations have won Nobel prizes from 1901 to 2011 and 199 persons have been awarded the Nobel Prize in Physiology or Medicine.

Each prize consists of a medal, a personal diploma and a cash award of 8 million Swedish kronor (about 1 million US dollars) for this year.