American geneticist Barbara McClintock discovered genetic elements of mobile nature referred as the “jumping genes.” Before her findings, genes were accepted as being static, with fixed locations in which cells were organized like a library. Her significant discovery in terms of the mobility of genes pioneered a new light on the workings of DNA.
Early Life of Barbara McClintock
Barbara McClintock was born on June 16, 1902 in Hartford, Connecticut, but she was raised in Brooklyn, New York. While attending Cornell University, she attended the only course in genetics that was available to undergraduate students and completed in 1923. She then pursued a Ph.D. in botany, also from Cornell, and obtained her doctorate four years later.
In 1936, she moved to the University of Missouri to work with Lewis Stadler. Later, she spent the summer at Cold Spring, Long Island, New York, as the guest investigator of maize geneticist Marcus Rhoades. She ultimately remained to work with Rhoades.
McClintock, Chromosomes and “Jumping Genes”
When McClintock started work as a geneticist and researcher, the concept was that genetic information was stored in chromosomes, the organized structure of DNA (contains instructions for living organisms to function) and protein found in cells of living bodies. Chromosomes were compared to reproducible data banks, or libraries. The chunks of chromosomes were called “genes.”
When she was offered the opportunity of pursuing her Ph.D. she had already decided that she wanted to pursue further studies on how genetic information is stored on the chromosomes.
In the summer of 1944, while working on the maize plant, she observed some startling results. Each cell in a maize plant has 10 pairs of chromosomes. She began to form an idea concerning the location of particular genes on individual chromosomes. Unperturbed by the apathy of some colleagues, she continued collecting data over the next five years.
Jumping Genes and Genetics
McClintock found that mobile gene elements could move from one chromosome to another. Also, a gene on one chromosome enables to influence the activity of a gene from another chromosome.
After she announced that some genes could jump anywhere within the chromosomes, now popularly coined as “jumping genes,” the simple concept of a fixed location became a complex reality with huge impact in the development of DNA.
McClintock Awards and Memberships
She was recognized among the best in her field and awarded distinguished and prestigious fellowships. In 1944, the year she identified “jumping genes” she was elected a member of the National Academy of Sciences – the third woman to be given the honor.
he was awarded the Nobel Prize in medicine or physiology in 1983.
Legacy and Contributions of Barbara McClintock
McClintock published her data about “jumping genes” in 1950. Primarily she worked on her own. And like Gregor Mendel, who discovered genetics, her work also gained the recognition it deserved many years after she announced her most significant findings. Her acquaintances include Lewis Stadler, George Wells Beadle and Marcus M. Rhoades.
Her discovery of the “jumping genes” has a profound influence on the understanding of genetics. In recent years, her research increased understanding of human diseases like cancer, and how bacteria can become resistant to drugs. Barbara McClintock died on September 2, 1992 in Huntington, New York.
Sources:
Clark, John, Ed. Illustrated Biographical Dictionary. London: Chancellor Press, 1978.
McGovern, Una, Editor. Chambers Biographical Dictionary. Edinburgh: Chambers, 2002.
Uglow, Jennifer (later revised by Maggy Hendry), Macmillan’s Dictionary of Women’s Biography. London: Macmillan, 1999.
Weatherford, Doris. American Women’s History. New York: Prentice Hall, 1994.
Comments