Barbara McClintock
LMR Barbara McClintock.jpg


Occupation
U.S. geneticist who discovered jumping genes (genes that can change their position on a chromosome from generation to generation), by that offering an explanation of how originally identical cells take on specialized tasks as skin, muscle, bone, and nerve, and also how evolution can give rise to the multiplicity of species. For this she was awarded a Nobel Prize for Physiology or Medicine in 1983. Unusually the award was not shared with another scientist.

Birth
June 6, 1902.
Death
September 2, 1992.
Place of Birth
LMR Map of Hartford Connecticut.jpg
Hartford Connecticut.

Known for
From 1941,Barbara McClintock studied corn chromosomes.


Science Explained
A chromosome is a DNA–protein difficult in the nucleus of eukaryotic cells. Chromosomes were so named because, after staining, nineteenth-century light microscopists saw chromosomes as colored bodies in cells. The combination of DNA and proteins in chromosomes is called chromatin. Collecting, the DNA from all the chromosomes in a nucleus is the traditional blueprint for the species. Eukaryotes (plants, animals, fungi, and protists) usually have one nucleus in each cell. A nucleus is a double membrane-bound compartment in which chromosomes are located in interphase between cell divisions. In contrast, prokaryotes, such as bacteria and their allies (including mitochondria and chloroplasts), do not have true chromosomes or nuclei because prokaryotes do not restrain their small, single circle of DNA in a membrane-bound section.

She recognized that the patterns on twin areas of corn seedlings were the opposite of one another, and that the color of certain kernels did not match to their genetic makeup. Realizing that as a single cell divided into sister cells, one gained what the other had lost, she deduced that not all genes behave in the same way: some genes can switch others on and off, moving from one place to another on one chromosome, or even “jumping” from one chromosome to another. These jumping genes acted as regulators and were later discovered in bacteria and in fruit flies.


She used X-rays to make chromosomal oddities and rearrangements and examin the ways in which chromosomes repair such damage. This information helped other scientists understand the problems of radiation sickness after the explosion of the atomic bomb at Hiroshima, Japan.




Career
Barbara McClintock worked at Cold Spring Harbor Laboratory, where she spent most of her professional life. She also did a lot of her when she was in college at Cornell University.

Did you know
McClintock’s work was ahead of its time and was for many years considered too fundamental—or was simply ignored—by her fellow scientists. Extremely disappointed with her classmates, she stopped publishing the results of her work and ceased giving lectures, though she continued doing research. Not until the late 1960s and ’70s, after biologists had determined that the genetic material was DNA, did members of the scientific community begin to confirm her early findings. When recognition finally came, McClintock was overwhelmed with awards and honors, most notably the 1983 Nobel Prize for Physiology or Medicine. She was the first woman to be the only winner of this award

Barbara McClintock was born with the name Eleanor McClintock, the third of four children born to physician Thomas Henry McClintock and Sara Handy McClintock. Thomas McClintock was the child of British immigrants, whereas Sara Handy, born with the name Grace, descended from an old American Mayflower family. Marjorie, the oldest child, was born in October 1898; Mignon, the second daughter, was born in November 1900. The youngest, Malcolm Rider (called Tom), was born 18 months after Barbara. As a young girl, her parents determined that Eleanor, a "feminine" and "delicate" name, was not right for her, and chose Barbara instead. McClintock was an independent child beginning at a very young age, a quality she later identified as her "capacity to be alone". From the age of three until she began school, McClintock lived with an aunt and uncle in Brooklyn, New York in order to reduce the financial problem on her parents while her father established his medical practice. She was described as a lonely and independent child, and a tomboy. She was close to her father, but had a difficult relationship with her mother, tension that began when she was young.
The McClintock family moved to Brooklyn, New York in 1908 and McClintock completed her secondary education there at Erasmus Hall High School; she graduated early in 1919. She discovered her love of science and reaffirmed her lonely personality during high school, and wanted to continue her studies at Cornell University's College of Agriculture. Her mother resisted sending McClintock to college, for fear that she would be unmarriageable. McClintock was almost prevented from starting college, but her father interfered just before registration began, and she enrolled at Cornell in 1919.

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References

"Barbara McClintock." Britannica School. Encyclopædia Britannica, Inc., 2013. Web. 19 Sep. 2013. < __http://school.eb.com/levels/middle/article/275577__.>

Hutchinson Dictionary of Scientific Biography, © RM, 2013, all rights reserved, as published under license in AccessScience, The McGraw-Hill Encyclopedia of Science & Technology Online, __http://www.accessscience.com__, © McGraw-Hill Education, 2000-2013. Helicon Publishing is a division of RM
Nobel Prize.org. “Barbara McClintock.” Nobel Prizes and Laureates. Nobel Media, 2013. Web.19 Sept. 2013.

Wikipedia. “Barbara McClintock.” Wikipedia, 23 Aug. 2013. Web. 18 Sept. 2013.