In 1987, University of California, San Diego Alumnus Susumu Tonegawa was awarded he Nobel Prize for Physiology or Medicine for his discovery of the genetic mechanism that produces antibody diversity.

In a pioneering study published in 1976, Tonegawa through a series of ingenious experiments showed how parts of the genome of the cell (DNA) is redistributed under its differentiation from an embryonic cell to an antibody producing B lymphocyte. During the following two years Tonegawa completely dominated this area of research.