Barbara McClintock (1902-1992), American geneticist. Gaining a Ph.D. in botany from Cornell University in 1927, Barbara McClintock went on to make her name in the study of the genetics of maize. Her most important work was in plant reproduction, where she discovered the moving of genes in chromosomes, by observing patterns of kernel colouration. She named these genes transposable elements. She showed how certain genes were responsible for certain physical traits in the maize. In 1983 she received the Nobel Prize in Physiology or Medicine for her work on 'mobile genetic elements'.