BoingBoing informs us that The Postal Service has scientist stamps, including Feynmann, von Neumann, Gibbs, and
Barbara McClintock (1902-1992)
In 1983, the renowned geneticist Barbara McClintock received the Nobel Prize in the category of "Physiology or Medicine" for discovering genetic transposition. McClintock's research on Indian corn plants led to her discovery that genetic material can change positions on a chromosome or move from one chromosome to another. Her discovery was confirmed immediately in corn and in the 1960s and 1970s in bacteria and other organisms.
It was at Cold Spring Harbor Laboratory in New York that she discovered transposition in the course of experiments on mutations caused by broken chromosomes. She called her mobile genetic elements "controlling elements," to indicate they controlled the action of other genes during development. McClintock was among the first biologists to think concretely about the way genetic material controls the development of the organism.
The one woman is also the only one not associated with physics. Nicely done.
But Post Office: Why only four?