John Gurdon from the UK and Shinya Yamanaka from Kyoto University in Japan have both taken the Nobel Prize in Medicine or Physiology for their work in stem cell research.

Gurdon and Yamanaka have been jointly awarded the prize for their work in transforming specialised cells into stem cells, which can become any other type of cell in the body.

The prize was awarded this morning at the Karolinska Institute in Sweden, and is the most coveted award in medical science.

Gurdon is currently the distinguished group leader in the Wellcome Trust/Cancer Research UK Institute in Cambridge.

His career has focused on nuclear transplantation in the frog and experiments to discover the value of mRNA microinjection, mechanisms of response to morphogen gradients, and more recently, mechanisms of nuclear reprogramming by Xenopus oocytes and eggs.

Gurdon discovered in 1962 that the specialisation of cells is reversible. In a classic experiment, he replaced the immature cell nucleus in an egg cell of a frog with the nucleus from a mature intestinal cell. This modified egg cell developed into a normal tadpole. The DNA of the mature cell still had all the information needed to develop all cells in the frog.

Yamanaka discovered more than 40 years later, in 2006, how intact mature cells in mice could be reprogrammed to become immature stem cells. Surprisingly, by introducing only a few genes, he could re-programme mature cells to become pluripotent stem cells, i.e., immature cells that are able to develop into all types of cells in the body.

These ground-breaking discoveries have completely changed our view of the development and cellular specialisation - scientists now understand that the mature cell does not have to be confined forever to its specialised state.

By reprogramming human cells, scientists have created new opportunities to study diseases and develop methods for diagnosis and therapy, and is something that pharma is beginning to invest more in, although successful R&D trials have been few and far between, as it is still a burgeoning area.