Nobel for the boy who was told he would never make a scientist

As a struggling 15-year-old, he was told by a teacher that even to think about a career as a scientist would be "a sheer waste of time". He came last out of 250 boys in his year for biology and was in the bottom set for every other science subject.

Sir John Gurdon was awarded the Nobel Prize in medicine, for work that led directly to the cloning of Dolly the sheep and the discovery that human adult cells can be reprogrammed to grow into any kind of body tissue. Gurdon shares the 750,000-pound prize money with Japanese Shinya Yamanaka, also a stem cell researcher.

Speaking on Monday, Sir John, 79, said his Eton school report still hung above his desk at the Gurdon Institute in Cambridge, which is named in his honour. It was the only item he had ever framed, he said. The schoolmaster concerned, a Gaddum, was a museum curator who had been hired to teach the lowest-achieving pupils, he explained.

"The main gist of it was that he had heard Gurdon was interested in doing science and that this was a completely ridiculous idea because there was no hope whatever of my doing science," Sir John added.

"When you have problems like an experiment doesn't work, which often happens, it's nice to remind yourself that perhaps after all you are not so good at this job and the schoolmaster may have been right."

After that assessment, the schoolboy switched his attention to classics and was offered an undergraduate place at Christ Church, Oxford. He was allowed to switch to zoology after a mix-up in the admissions office and it was as an Oxford postgraduate student that he published his ground-breaking research, proving for the first time that every cell in the body contains the same genes. He took a cell from an adult frog's intestine, removed the DNA and implanted it into an egg cell, which grew into a clone of the adult frog.

The work contradicted previous studies by far more senior scientists, and it took a decade before it was widely accepted. It led to the cloning of Dolly, the first mammal created that way, by Prof Ian Wilmut in Edinburgh in 1996, and then to the discovery by Prof Yamanaka that adult cells themselves could be "reprogrammed" into stem cells. These can then turn into any tissue in the body, and are already being used in trials to repair damaged tissue in heart attack patients. Sir John said it would have been "particularly nice" if Prof Wilmut had shared the award.

Sir John, who celebrated with drinks at Cambridge on Monday night, joined the university in 1971 following spells at the California Institute of Technology and Oxford, and in 1989 helped found the Wellcome/CRC Institute for Cell Biology and Cancer - later renamed the Gurdon Institute - where he still works full-time.