Dr. John B. Gurdon, a British biologist and Nobel laureate who in the early 1960s introduced a paradigm-shifting method of cell manipulation that led to the world’s first cloning of a large mammal, a sheep named Dolly, died on Tuesday. He was 92.
His death was confirmed by Ben Simons, the director of the Gurdon Institute, a research center founded in Gurdon’s name in 1991 at the University of Cambridge in England. He did not specify where Gurdon died or cite the cause.
An emeritus professor at the university, Gurdon was a giant in the field of developmental biology. His lifelong work in the study and manipulation of cells laid the foundation for stem cell biology and the discipline of regenerative medicine, an emerging process of manipulating patients’ cells to produce replacement organs or tissues.
Gurdon first came to global prominence in 1962 as a graduate student at the University of Oxford, with the publication of his now classic experiments involving the cloning of the frog species Xenopus laevis.
In that research, he extracted the nuclei from the intestinal cells of a mature frog, which contained the amphibian’s DNA. He then injected the nuclei into frog egg cells whose nuclei had been removed. The eggs efficiently “reprogrammed” the genes in the transplanted nucleus: They switched from performing the role of a highly differentiated intestinal cell to reproducing an organism, a process known as nuclear reprogramming.
At the time, scientists believed that a specialized cell, like an intestinal cell, was incapable of performing duties other than those of an intestinal cell. The experiment, in Oxford’s embryology laboratory, proved that cells retain all of their genetic information no matter how specialized.
“Dr. Gurdon challenged the dogma that the differentiated state was fixed and irreversible,” Helen Blau, director of the Baxter Laboratory for Stem Cell Biology at Stanford University in Palo Alto, California, said in an interview for this obituary in 2024. “He showed that if a nucleus was removed and transplanted into an enucleated frog egg, that a swimming tadpole would develop.”
Blau was an undergraduate in 1969 when she first learned of Gurdon’s experiments and was so inspired by them, she said, that she began to build on his work. By the 1980s, she had demonstrated that nuclear reprogramming was not limited to amphibians but possible in mammals, too.
Blau and her team of stem cell biologists say that Gurdon further proved that nuclear reprogramming is an ideal method of obtaining pluripotent stem cells, the blank slates capable of morphing into any kind of cell type. Pluripotent stem cells are studied in research on cancer and the regeneration of nerves for people who have lost the function of limbs.
“It was a deceptively simple experiment,” Dr. Douglas Melton, co-director of the Harvard Stem Cell Institute, said of the Xenopus laevis study in an interview. He was a graduate student in Gurdon’s lab at the University of Cambridge from 1975 to 1980. “John demonstrated that cells retain all of their genes,” Melton said, “and through nuclear reprogramming you can take them back to the beginning.”
Gurdon’s amphibian research, followed by Blau’s mammalian studies in nuclear reprogramming, laid the intellectual groundwork for the cloning of Dolly in 1996 in Scotland.
But it wasn’t until 2006 that scientists fully understood how nuclear reprogramming, which Gurdon had documented for decades, worked at all. In Japan, Shinya Yamanaka found that nuclear reprogramming occurs when DNA-controlling agents, known as transcription factors, coax lab-manipulated cells to respond to a nucleus transplant roughly to the way an egg cell would react when fertilized by sperm.
Gurdon and Yamanaka shared the 2012 Nobel Prize in physiology or medicine for their discovery.
John Bertrand Gurdon was born on Oct. 2, 1933, in the English hamlet of Dippenhall to William Nathaniel Gurdon and Elsie (Byass) Gurdon. He had a sister, Caroline. His father was a banker who retired in his 40s and later earned a living transcribing textbooks into Braille. William Gurdon hailed from a long line of distinguished Gurdons dating back nearly 1,000 years in British history.
Gurdon attended private elementary schools and enjoyed entomology, raising moths and butterflies at home. At age 13, he was sent to board at Eton, where he brought along his jars of caterpillars. Two years into his studies there, however, a teacher strongly dissuaded him from studying biology and other sciences.
In a scathing note to him, the teacher wrote: “I believe Gurdon has ideas about becoming a scientist. On present showing, this is quite ridiculous.”
Gurdon kept the note throughout his life, and a copy is posted on his biographical page of the Nobel Prize website.
“That was a pretty crippling introduction to biology,” Gurdon said in an interview in 2008 in the Journal of Cell Biology. The note had a rippling effect, causing him to be barred from all sciences at Eton. The school’s masters forced him to focus, instead, on Ancient Greek and Latin.
Immediately after Eton, he was admitted to Oxford University, but that damning note also affected his eligibility to enroll in the sciences there. Without a secondary-school science record, he couldn’t major in zoology, the discipline he had hoped to study. That compelled his parents to intervene, by arranging two years of tutoring in the sciences.
He finally entered Oxford in 1953, and as an undergraduate made the first major discovery of his career. While walking in woods in Oxford, he came upon an insect that at first blush looked something like a common housefly — but not exactly. He captured the specimen, he told the journal Development in 2017, and took it to the university’s entomologists. They were stumped. He then brought the insect to the Natural History Museum in London, where a curator identified the insect as a Hymenopteran, commonly known as a sawfly, the first ever found in England. Gurdon wrote about the discovery in an entomology magazine in 1954.
He graduated from Oxford in 1956 and soon began postgraduate work there, finishing his doctorate in 1962. After a year of postdoctoral study at the California Institute of Technology, he returned to England, where he met and married Jean Elizabeth Curtis, the daughter of a business owner in the city of Oxford. They had two children, Aurea and William.
His wife and children survive him, as do two grandchildren.
In addition to the Nobel Prize, Gurdon received numerous honors, including the Wolf Prize, an Israeli international award in the sciences, and the Lasker Award, often called the American Nobel. He was knighted by Queen Elizabeth II in 1995 for his scientific contributions.
“John was always very curious,” Melton said in the 2024 interview. “To him, science was a wonderful life, and he thought everyone should participate in it. He trained a whole generation of scientists. The world’s universities are populated with his proteges.”
This article originally appeared in The New York Times.
Dr. Gurdon first came to global prominence in 1962 as a graduate student at the University of Oxford, with the publication of his now classic experiments involving the cloning of the frog species Xenopus laevis. (Credit: nobelprize.org) 
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