A totipotent embryologist: John B. Gurdon (1933–2025)

John Gurdon was a curiosity-based inquisitor of embryonic development, beguiled by its mysteries, and he stayed with this focus all his career. His landmark cloning of Xenopus laevis using a donor nucleus from adult somatic tissue conclusively settled a longstanding question and was foundational to cloning of a mammal and subsequent advances in nuclear reprogramming. He was awarded the 2012 Nobel Prize in Physiology or Medicine. As a person, Gurdon was confident but not arrogant, an elegant writer and speaker, a warm colleague, and a revered mentor of those fortunate to have worked with him. We may not see his like in developmental biology anytime soon, or in biology altogether.