Susumu Tonegawa, Japanese biologist and immunologist, Nobel Prize laureate

Susumu Tonegawa is a Japanese scientist who was the sole recipient of the Nobel Prize for Physiology or Medicine in 1987 for his discovery of V(D)J recombination, the genetic mechanism which produces antibody diversity. Although he won the Nobel Prize for his work in immunology, Tonegawa is a molecular biologist by training and he again changed fields following his Nobel Prize win; he now studies neuroscience, examining the molecular, cellular and neuronal basis of memory formation and retrieval.

The Nobel Prize in Physiology or Medicine is awarded yearly by the Nobel Assembly at the Karolinska Institute for outstanding discoveries in physiology or medicine. The Nobel Prize is not a single prize, but five separate prizes that, according to Alfred Nobel's 1895 will, are awarded "to those who, during the preceding year, have conferred the greatest benefit to humankind". Nobel Prizes are awarded in the fields of Physics, Medicine or Physiology, Chemistry, Literature, and Peace.