Developmental biologist Sir John Bertrand Gurdon, co-winner of the 2012 Nobel Prize in Physiology or Medicine and a former Caltech postdoctoral researcher, passed away October 7, 2025, at the age of 92.
Gurdon was awarded the Nobel Prize for his pioneering research in nuclear transfer, showing that mature cells can be reprogrammed to serve as stem cells. That is, he found that even after cells have become differentiated to perform specialized tasks in the body, they still contain all the DNA that is required to reproduce an entire organism. The prize was shared with Shinya Yamanaka of Kyoto University.
Born in 1933, Gurdon grew up on a farm in southern England near the Surrey/Hampshire border during World War II, where he showed an early interest in the life cycle of butterflies and moths. He attended Eton from age 13. Famously, at age 15 Gurdon placed last in his biology class of 250 boys. The biology master wrote on Gurdon's report, "I believe he has ideas about becoming a scientist; on his present showing this is quite ridiculous; if he can't learn simple biological facts he would have no chance of doing the work of a specialist, and it would be a sheer waste of time, both on his part and of those who would have to teach him." Gurdon's housemaster did not allow him to take any further science courses and so he spent the remainder of his time at Eton studying languages, including ancient Greek and Latin.
Gurdon was admitted to Oxford University to study classics in 1952 but instead took a year off to study physics, chemistry, and biology. He then entered Oxford in 1953 as a student of zoology. Afterward, he continued with his doctoral work at Oxford studying developmental biology. As a PhD student, Gurdon was introduced to Xenopus, a species of aquatic frogs that grow their eggs on the outside of their bodies. Within a few days the eggs become transparent, which makes this frog an ideal subject for studying developmental biology. Xenopus was to accompany Gurdon throughout his career.
For his doctoral thesis work, Gurdon took on the challenge of transplanting the nuclei of cells from a frog's intestine into the frog's egg; this provided the egg with the genetic information needed to produce a tadpole. This discovery raised the possibility of using cell replacement from easily accessible parts of the body, such as skin, to treat diseases anywhere in the body. The finding was not immediately accepted by the scientific community, however, so Gurdon continued to reproduce these experiments over the years to confirm his finding.
Following his doctoral work, Gurdon studied the genetics of phages—viruses that infect and reproduce within bacteria—at Caltech with geneticist Robert Edgar. Though Gurdon chose not to continue research in this area, he regarded his time at Caltech as pivotal for the opportunity it provided him to study molecular biology.
Following his postdoctoral studies, Gurdon returned to Oxford as an assistant lecturer in zoology. He was also offered a position as a research fellow, which enabled him to establish his own lab. In 1972, he was offered a faculty position at Cambridge, where he eventually established a research institute that included students and postdoctoral fellows from a variety of scientific fields adjacent to zoology. He served as master of Magdalene College from 1995 to 2002, using his salary to hire a professional fundraiser so that he could be freed up to pursue his laboratory work. During this time, he also served as governor of The Wellcome Trust in London and as president of the International Society of Developmental Biologists. In 2004, the Wellcome Trust/Cancer Research UK Institute for Cell Biology and Cancer at Cambridge was renamed the Gurdon Institute.
Gurdon was elected to the American Academy of Arts and Sciences, the National Academy of Sciences, the American Philosophical Society, and the American Association for Cancer Research in the United States, and the Cambridge Philosophical Society, the Academy of Medical Sciences, the Anatomical Society, the Royal College of Physicians, and the Royal Society of Biology in England. He won the Wolf Prize in Medicine in 1989 for the work that was later honored with the Nobel Prize. In 1995, he was knighted by Queen Elizabeth for his services to developmental biology.
Upon his passing, Ben Simons, the current director of the Gurdon Institute at Cambridge University commented, "As well as being a towering figure in developmental and stem cell biology, through his dedication to science, his affection for colleagues and his humility, Sir John Gurdon was an inspiration to us all."