Portrait of Barbara McClintock, 1947THE BARBARA MCCLINTOCK COLLECTION, COLD SPRING HARBOR LABORATORY ARCHIVES
Barbara McClintock’s pioneering work in genetics began just two decades after biologists rediscovered Gregor Mendel’s work on heredity in 1900. After refining chromosome-staining techniques, McClintock became the first person to visualize and count the chromosomes of maize in 1928—a feat that jump-started her lifelong career in cytogenetics. In 1931, McClintock and her student Harriet Creighton used the characteristic structure of chromatin to demonstrate that genes corresponded to physical locations on chromosomes. Using an identifying knob on chromosome 9 as a guidepost, they localized certain traits on the chromosome, and demonstrated that chromosomes could “cross-over” and exchange genetic information. McClintock was awarded a Nobel Prize in 1983 for the discovery of transposable elements—snippets of the genome that can be prompted to switch places, often influencing gene ...
