Discovery of transposable elements ('jumping genes') in maize (1940sā1950)
Genetic elements that move position on chromosomes and switch other genes on and off
Science Ā· Biology
Barbara McClintock
1902ā1992 Ā· American
Cytogenetics; maize genetics
Barbara McClintock was an American cytogeneticist who spent her career studying the chromosomes of maize (corn). At Cold Spring Harbor in the 1940s and 1950s she discovered transposable elements, or "jumping genes", an idea largely ignored for decades. She was vindicated when she received the unshared 1983 Nobel Prize in Physiology or Medicine.
How to spot them
- āøMaize (corn) and its multicoloured kernels; Cold Spring Harbor
- āøTransposons or 'jumping genes'; the Activator (Ac) and Dissociation (Ds) elements
- āøSole, unshared Nobel Prize in Physiology or Medicine, 1983
- āøEvelyn Fox Keller's biography 'A Feeling for the Organism'
Key discoveries & works
The Activator/Dissociation (Ac/Ds) system (1948ā1950)
The first transposable elements described, which caused mottled colouring of maize kernels
Cytological proof of crossing over in maize (with Harriet Creighton) (1931)
Showed that genetic recombination corresponds to a physical exchange of chromosome segments
Identification of the ten chromosomes of maize (late 1920s)
Developed staining techniques at Cornell to tell the individual maize chromosomes apart
Key ideas
- Genomes are not static: some genetic elements can move and regulate other genes
- Her 'controlling elements' anticipated later understanding of gene regulation
Quick-fire facts
- ā¢Born in Hartford, Connecticut; studied and took her PhD at Cornell University
- ā¢Worked at Cold Spring Harbor Laboratory on Long Island from 1942
- ā¢Won the unshared 1983 Nobel Prize in Physiology or Medicine 'for her discovery of mobile genetic elements'
- ā¢First woman to win an unshared Nobel Prize in Physiology or Medicine
- ā¢Elected to the US National Academy of Sciences in 1944, only the third woman so honoured
- ā¢Received the US National Medal of Science in 1970
- ā¢Subject of Evelyn Fox Keller's biography 'A Feeling for the Organism' (1983)
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Sources
- The Nobel Prize ā Barbara McClintock ā Facts
- National Women's History Museum ā Barbara McClintock
- Evelyn Fox Keller ā A Feeling for the Organism