Susumu Tonegawa, the Nobel Prize-winning molecular biologist whose experiments showed how the immune system manufactures a vast repertoire of antibodies and who later helped map how memories are stored, died July 11 at his home in San Mateo, California. He was 86. Over a career that moved from immunology to neuroscience, Tonegawa built the laboratory community that became MIT’s Picower Institute for Learning and Memory and mentored generations of scientists.
How a handful of genes became the answer
In the 1970s and early 1980s, Tonegawa demonstrated that B cells assemble antibody genes by recombining variable, diversity and joining segments, a process now known as V(D)J recombination. The Nobel committee recognized that breakthrough with the 1987 Nobel Prize in Physiology or Medicine, according to The Nobel Prize.
A second act in memory research
After his immunology breakthrough, Tonegawa turned to the brain and led experiments that identified memory “engrams,” ensembles of cells that encode episodic memories, and showed they could be activated or altered in mice. Those later discoveries and his broader contributions to learning and memory are summarized by the Picower Institute, which published an in memoriam notice this month.
MIT, RIKEN and colleagues react
MIT confirmed that Tonegawa died July 11 at his home in California and published an obituary this week. Colleagues and former students described his intellectual restlessness and breadth of influence. “Few scientists have reshaped our understanding of biology as profoundly as Susumu Tonegawa,” Myriam Heiman, director of the Picower Institute, told MIT News. Japan’s RIKEN institute issued a statement praising his leadership of the RIKEN Brain Science Institute and the enduring impact of his engram work, according to RIKEN.
Legacy and family
Tonegawa received many of science’s top honors beyond the Nobel and continued publishing into his 80s; his labs have seeded much of modern engram research. Picower Institute reports that he is survived by his wife, Mayumi, two children and two grandchildren, and that his ashes will be buried in Kyoto. His work continues to shape both immunology and neuroscience worldwide.
National outlets have also run obituaries and retrospectives on his life and science; for a fuller account, see The New York Times.
