Barbara McClintock (June 16, 1902 – September 2, 1992) was an American biologist. She was a distinguished cytogeneticist who worked on inheritance in maize. McClintock was awarded the 1983 Nobel Prize in Physiology or Medicine.
McClintock got her PhD in botany from Cornell University in 1927. Maize cytogenetics was the focus of her research for the rest of her career.
From the late 1920s, McClintock studied chromosomes and how they change during reproduction in maize. She used microscopic analysis to show genetic recombination by crossing-over during meiosis—a mechanism by which chromosomes exchange information.
She produced the first genetic map for maize, and demonstrated the role of the telomere and centromere. These are regions of the chromosome that are important in preserving genetic information.
She was recognized amongst the best in the field, awarded prestigious fellowships, and elected a member of the National Academy of Sciences in 1944.
During the 1940s and 1950s, McClintock discovered transposition and used it to show how genes are responsible for turning physical characteristics on or off. She developed theories to explain the control of genetic information from one generation of maize plants to the next. Encountering skepticism of her research and its implications, she stopped publishing her data in 1953. Later, she made an extensive study of the cytogenetics of maize races from South America.
McClintock's research became well understood in the 1960s and 1970s, as researchers discovered the mechanisms behind the genetic change and gene regulation that she had shown in her maize research in the 1940s and 1950s.
Awards and recognition for her contributions to the field followed for the discovery of transposons; she is the only woman to receive an unshared Nobel Prize in the category 'Physiology or Medicine'.