Barbara McClintock (June 16, 1902 – September 2, 1992) was an American scientist and
cytogeneticist who was awarded the 1983
Nobel Prize in Physiology or Medicine. McClintock received her
PhD in
botany from
Cornell University in 1927. There she started her career as the leader in the development of
maize cytogenetics, the focus of her research for the rest of her life. From the late 1920s, McClintock studied
chromosomes and how they change during reproduction in maize. She developed the technique for visualizing maize chromosomes and used microscopic analysis to demonstrate many fundamental genetic ideas. One of those ideas was the notion of
genetic recombination by
crossing-over during
meiosis—a mechanism by which chromosomes exchange information. She produced the first
genetic map for maize, linking regions of the chromosome to physical traits. She demonstrated the role of the
telomere and
centromere, regions of the chromosome that are important in the conservation of
genetic information. She was recognized among the best in the field, awarded prestigious fellowships, and elected a member of the
National Academy of Sciences in 1944.