October 19, 2010

Barbara McClintock Won Nobel Prize for ‘Jumping Genes,’ Became Female Role Model

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Barbara McClintock was the first female Nobel Laureate for Physiology or Medicine to receive the prize unshared. She is celebrated today, among other things, for discovering transposable elements, for which she received the Nobel Prize in 1983.

Transposable elements, also known as “jumping genes,” are pieces of DNA that move from one place to another in genomes. McClintock first found these transposons in maize in 1948 when she noticed insertions, deletions, and translocations in the maize genome. She suspected that transposable elements can cause mutations and control genes.

Her interest in genetics stemmed from the genetics course she took at Cornell University as an undergraduate. After she graduated, McClintock studied the fundamental ideas of genetics.

She led the research on maize – she produced its first genetic map, established its life cycle, and showed how it could be used as a tool for genetics. She demonstrated that the genetic phenomenon of “crossing-over” involves the physical exchange of material between chromosomes during meiosis.

Now, her name is seen in numerous textbooks. However, she  received this fame late in her career.

Feminists argue that she did not receive as much recognition as she deserved because she was a woman when there were very few female geneticists.

“It’s true that there was an old-boys network,” Prof. Michael Goldberg, molecular biology and genetics, remarked. “But it’s also true that senior scientists at the time respected her work.”

Goldberg gave three possible reasons why the discovery of transposons may not have been widely recognized: her papers were hard to read, there was no basis for understanding jumping genes because no one knew how to look at DNA, and while transposons can affect genes, they did not control the genes normally as she proposed.

She was also “very private and did most of her experiments by herself, just looking into the microscope,” commented Goldberg.

“She lived an almost ascetic kind of life. Clearly, she didn’t think much about money and position,” Goldberg reflected as he told a story.

He had the chance to meet her in the mid ’70s when she worked at Cold Spring Harbor. Goldberg, a graduate student, went to learn research techniques that had been developed there.

“One of my fondest memories was just walking all over Long Island with her telling me about the life cycles of various organisms and about her thoughts on science.”

She was never a professor, but she was always interested in teaching young students. When she was invited back to Cornell, as an professor, “she never wanted to speak with the professors, but rather talked to the grad students,” said Goldberg. “She also wanted to sleep in the dormitories.”

“Many people regarded her as kind of eccentric … It’s true in a narrow sense, but she was just driven by science; that was the main thing in her life.”

Original Author: Yoshiko Toyoda