Today’s Nobel Prize in medicine went to Shinya Yamanaka and John Gurdon for their work on stem cell research and cloning.

The Nobel Prize announcement describes their contributions this way:

The Nobel Prize recognizes two scientists who discovered that mature, specialised cells can be reprogrammed to become immature cells capable of developing into all tissues of the body. Their findings have revolutionised our understanding of how cells and organisms develop.

In the 1950s, John Gurdon discovered that if you transfer nuclei from egg cells into an adult cell, you wind up making cells that forget where they came from—they look like embryonic cells. This is a big deal: once you’re an adult, your cells are specialized. A skin cell is a skin cell, a neuron is a neuron, a blood cell is a blood cell. But Gurdon’s work showed that you can reverse that specialization. His experiment, in which he put a mature nucleus from a frog’s intestine into an immature frog egg and grew a totally normal tadpole, paved the way for modern stem cell research.

This discovery was met with skepticism, the Nobel Prize committee writes. With other scientists eager to prove or disprove the idea, Gurdon’s work “initiated intense research and the technique was further developed, leading eventually to the cloning of mammals.” Gurdon eventually gained the nickname “the godfather of cloning.”

Other scientists weren’t the only ones skeptical of Gurdon. His own science teacher told him to give up science. Thankfully, he didn’t listen. The Agence France-Presse writes:

Gurdon is fond of recalling that when he was 15, a tutor wrote in his school report that it would be a “total waste of time” if he followed a career in biology “and this whole idea should be immediately discouraged”. He has said he keeps the report above his desk “for my amusement”.

Shinya Yamanaka’s work came nearly forty years after Gurdon. The Lasker Foundation writes:

In 1999, Shinya Yamanaka began to wonder whether he could devise a nuclear-reprogramming method that would circumvent these hurdles. He knew that the late Harold Weintraub had shown in 1988 that a single gene could convert fibroblasts, a type of connective tissue cell, into muscle cells. If nuclei from fully differentiated cells could be genetically re-set, Yamanaka reasoned, and if one gene could force a certain cell type to behave like another, perhaps he could reprogram adult cells to an embryonic state by adding to them a small number of factors.

What he found was that just four factors could totally reset the specialization of a cell. Introduce these genes in various combinations, and it’s possible to turn adult cells back into stem cells. These born-again cells are called induced pluripotent stem cells (iPS) and can develop into all sorts of tissues.

You don’t win the Nobel Prize for just fun and games in a lab. These breakthroughs have some serious implications for medicine. Here’s the Nobel Prize Assembly again:

For instance, 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 individuals. Such cells constitute invaluable tools for understanding disease mechanisms and so provide new opportunities to develop medical therapies.

And the Lasker Foundation:

The conceptual and technical breakthroughs spearheaded by Gurdon and Yamanaka have unleashed previously unimagined strategies for combating diseases and probing normal development as well as pathological processes. They have launched an era in which scientists can reverse the clock to fashion cells that possess all possible fates from those that have arrived at a single one.

More from Smithsonian.com:

Stem Cell Pioneers