Susumu Tonegawa was born in Japan in 1939 but has worked most of his career in the United States. Hw was awarded the 1987 Nobel Prize in Medicine for developing thetechniques that showed that antibody diversity was generated by recombination of multiple genes. He pursued the first evidence that gene rearrangements were invovled in creating antibody diversity. By using restriction enzymes and recombinant DNA techniques he showed how B cell generated different antibody molecules by recombination between multiple gene segments and has also shown that T cell receptors do exactly the same

Tizard An introduction to Immunology 4th Ed p 215