Barbara Mcclintock
1902-1992
American Geneticist
Barbara McClintock discovered that certain types of genes, called "jumping genes," can move from one place on a chromosome to another, from one generation to the next. For this discovery she was awarded the 1983 Nobel Prize in Physiology or Medicine.
Born in Hartford, Connecticut, on June 16, 1902, McClintock attended Erasmus Hall High School in Brooklyn, then went on to Cornell University, where she earned her bachelor's degree in 1923. As an undergraduate she was very active in social activity, playing the banjo in a jazz band and serving as president of the freshmen women's class. She soon became absorbed in her studies and retreated from social activities to pursue academics. At that time genetics was still a relatively new field, as it had been only 21 years since the rediscovery of Mendel's principles of heredity. However, interest in genetic research was growing. In January 1922 McClintock was invited by Dr. Hutcheson to attend his class on genetics, the only course of its type then offered at Cornell. This proved a momentous event, as McClintock found her life's work in genetics.
Barbara McClintock. (UPI/Corbis-Bettmann. Reproduced by permission.)As McClintock worked on her master's degree, she became fascinated by the structure of chromosomes and the role of mitosis and meiosis. She completed her Ph.D. in 1927 and remained at Cornell to study the 10 chromosomes of maize. At that time Cornell did not appoint women as faculty professors. After 11 years as an instructor and researcher, she accepted a position as assistant professor of botany at the University of Missouri, where she remained for five years. That was the last time she taught, for she began to do research exclusively. In 1942 she moved to Cold Springs Harbor, New York, where she continued to work long hours, seven days a week, until just before her death. She even had a small apartment on the grounds of the laboratory.
Concentrating her efforts on the genetics and cellular composition of maize, or corn, McClintock observed variations among kernels of corn and found that genetic information does not stay in one place. Tracing pigmentation changes and examining the large chromosomes under a microscope, she found two genes were "controlling" elements. These genes actually told the other genes what to do by moving along a gene at a different site. She dubbed these "jumping genes" and suggested these transposable genes were responsible for mutations. This research, initially conducted in 1944, was not recognized until the 1960s,when scientists learned the genetic material was DNA and two French scientists discovered genetic anomalies in bacteria similar to those McClintock earlier observed in corn.
McClintock's work subsequently won recognition for its great contribution to the understanding of genetic function and organization. In 1970 she received the National Medal of Science. She received many additional medals and prizes, including the prestigious Nobel Prize in 1983.
McClintock had many personal and professional challenges. Her independence, originality, and accomplishments were intimidating to many of her colleagues. Living at a time when genetics was beginning to come into its own, she saw her work go unrecognized for many years. However, her groundbreaking research established her as a leader in the field of genetics. She died in Huntington, Long Island, on September 2, 1992.
This is the complete article, containing 537 words
(approx. 2 pages at 300 words per page).
