By Kristy McCaffrey
Barbara McClintock was an American scientist and
cytogeneticist who made the first genetic map of maize, and in the process
discovered jumping genes.
Jumping genes, or transposons, are small pieces of DNA that have
the unusual ability to copy and insert themselves in random places within a
genome. These genes—long known as junk DNA—were thought to be nothing more than
genomic parasites, but research is beginning to show their importance in
evolution.
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| Barbara McClintock in her lab, 1947. |
McClintock, the third of four children, was born in 1902 to
a homeopathic physician. Named Eleanor at birth, her parents later changed it
to Barbara when they decided she needed a less “delicate” name. An independent
child who liked to be alone, she was close to her father but had a difficult
relationship with her mother. When Barbara wanted to attend college, her mother
was against it, believing it would make her daughter unmarriageable. But her
father intervened and she enrolled at Cornell, eventually receiving her Ph.D.
in Botany in 1927.
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| McClintock's microscope and ears of corn on exhibit at the National Museum of Natural History. |
In the 1940s, McClintock discovered the transposition of
genes and the ability of these genes to turn physical characteristics on and
off in maize. She developed theories to explain the suppression and expression
of genetic information from one generation of maize plants to the next. But due
to skepticism of her work, she stopped publishing her research in 1953.
In the 1960s and 70s, her work became more understood and
confirmed by other scientists, and in 1983 she was awarded the Nobel Prize in
Physiology or Medicine for the discovery of genetic transposition, the only
woman to receive an unshared Nobel Prize in that category.
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| McClintock giving her Nobel lecture. |
She never married or had children, and died in 1992 at the
age of 90.
