Barbara McClintock
She is known for her discovery of transposons, or 'jumping genes,' and for her pioneering work in maize cytogenetics, which demonstrated fundamental mechanisms of genetic recombination, chromosome structure, and gene regulation.
- born
- June 16, 1902, Hartford, Connecticut
- died
- September 2, 1992
- field
- Cytogenetics, Botany
- nationality
- American
- known_for
- Discovery of transposons; genetic recombination by crossing-over; role of telome
Lore & Background
Her parents renamed her Barbara, deeming Eleanor too 'feminine.' She lived with an aunt and uncle in Brooklyn from age three until starting school, and was described as solitary and independent. At Cornell, McClintock led the development of maize cytogenetics. She developed a technique using carmine staining to visualize maize chromosomes and demonstrated the morphology of the 10 maize chromosomes. In 1930, she first described the cross-shaped interaction of homologous chromosomes during meiosis. She also identified ring chromosomes in maize after X-ray mutagenesis and hypothesized a structure on the chromosome tip ensuring stability. During the 1940s and 1950s, she discovered transposons and showed that genes can turn physical characteristics on and off. Due to skepticism, she stopped publishing her data in 1953. Later, she studied the cytogenetics and ethnobotany of maize races from South America.
Reader's Guide
Barbara McClintock's significance lies in her foundational contributions to genetics, particularly the discovery of transposons—mobile genetic elements that can change position within the genome. Her earlier research on maize chromosomes established key concepts: genetic recombination via crossing-over during meiosis, the roles of telomeres and centromeres in preserving genetic information, and the first cytogenetic map linking chromosome structure to inherited traits. Her techniques for visualizing chromosomes became standard in textbooks. McClintock's legacy endures as a pioneer who revealed the dynamic nature of the genome, influencing fields from molecular biology to evolutionary genetics. Her career also highlights the challenges faced by women in science, as she overcame early resistance to her education and later professional skepticism.
Did You Know?
- Barbara McClintock was born Eleanor McClintock, but her parents renamed her Barbara because they considered Eleanor too 'feminine.'
- She was the only woman to receive an unshared Nobel Prize in Physiology or Medicine as of 2025.
- In 1931, with Harriet Creighton, she proved the link between chromosomal crossover during meiosis and the recombination of genetic traits.
- Due to skepticism about her transposon discovery, she stopped publishing her data in 1953.
- She studied the cytogenetics and ethnobotany of maize races from South America later in her career.
Frequently Asked Questions
Who is Barbara McClintock?
She was an American cytogeneticist and botanist born in Hartford, Connecticut, in 1902. Her career was devoted to maize genetics, where she uncovered fundamental mechanisms of chromosome structure and gene regulation.
What is Barbara McClintock most famous for discovering?
She identified transposons, often called 'jumping genes,' which are DNA segments capable of relocating within a genome. This finding revealed a previously unknown mechanism of genetic recombination and gene regulation.
What major award did Barbara McClintock receive?
She was awarded the 1983 Nobel Prize in Physiology or Medicine. The honor recognized her groundbreaking maize cytogenetics work and her identification of transposons.
What organism did Barbara McClintock use for her research?
Her pioneering cytogenetic work was conducted primarily on maize (corn). She developed techniques to visualize maize chromosomes, which let her trace crossing-over recombination and the roles of telomeres and centromeres.
When did Barbara McClintock live?
She was born on June 16, 1902, in Hartford, Connecticut, and died on September 2, 1992. Her scientific career spanned much of the twentieth century, culminating in her 1983 Nobel recognition.
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