George Wells Beadle

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George Wells Beadle (October 22, 1903 – June 9, 1989) was an  American scientist in the field of genetics. He shared half of the 1958  or  Medicine">Nobel Prize in Physiology or  Medicine with Edward Lawrie Tatum for their discovery that genes act by regulating biochemical events within the cell. The other half of that year's award went to Joshua Lederberg.

Beadle and  Tatum's key experiments involved exposing the bread mold Neurospora crassa to x-rays, causing mutations. In a series of experiments, they showed that these mutations caused changes in specific enzymes involved in metabolic pathways. These experiments led them to propose a direct link between genes and  enzymatic reactions, known as the "one gene, one enzyme" hypothesis.

[ and  work">edit] Life and  work

Beadle was born in Wahoo, Nebraska. He received his Bachelor of Science degree in agronomy from the University of Nebraska's College of Agriculture in 1926. At the recommendation of his advisor, Franklin D. Keim, he then entered graduate school in agronomy at Cornell University, intending to study ecology. He soon switched his focus to genetics and  cytology, pursuing research on maize (corn) genetics under Rollins Adams Emerson—including some collaboration with Barbara McClintock. He received his Ph.D. from Cornell in 1931.^[1]

For post-doctoral work, Beadle joined Thomas Hunt Morgan's "fly lab" at the California Institute of Technology, where he worked with Alfred Sturtevant and  others on Drosophila genetics. There, working with Boris Ephrussi, he helped develop a technique for transplanting foreign cells in fly larvae (creating a third eye in flies' abdomens); this technique was used to demonstrate that some mutations affecting eye color involved genes that controlled specific metabolic steps in the production of eye pigment. In an  effort to precisely characterize the reactions and  substances involved, he recruited biochemist Edward Tatum to work on the pigment problem as well. They eventually isolated and  identified the pigment precursor found in the "vermilion" mutant, but did so shortly after an  independent German group. Over the course of his Drosophila work, Beadle was a professor at Harvard University, then Stanford University.^[2]

With Tatum, Beadle switched his focus to a model organism more  suited to biochemical genetics: Neurospora. By constructing mutant strains that required specific nutritional elements (amino acids or  vitamins), they established that individual gene mutations were responsibile for individual steps in the metabolism and  synthesis of vital nutrients. This led, in 1941, to propose the "one gene-one enzyme hypothesis," the idea that a gene specifies a single enzyme, rather than a complex set of characteristics (as was generally assumed).^[3]

In 1946, with the support of Linus Pauling, Beadle was recruited to head the newly reorganized biology division of Cal Tech; the department was one of the protypes of what would become known as molecular biology. During the early Cold War, Beadle was outspoken in his defense of colleagues under investigation for suspected Communist ties, and  also worked on defining and  publicizing the potential dangers of nuclear weapons-related radiation. In 1958, Beadle and  Tatum were awarded the Nobel Prize in Physiology and  Medicine for their work on biochemical genetics. Beadle went on to serve as president of the University of Chicago from 1961-1968, helping—through fund-raising and  recruitment—to re-establish its reputation as a top research university. He published a book, The Language of Life, in 1966.^[4]

Following his retirement as university president, returned to research, now on the evolutionary relationship between corn and  teosinte. He continued research until the late 1970s, when Alzheimer's disease made continued intellectual work impossible. George Beadle died in 1989; his second wife Muriel Barnett Beadle died in 1994. He had one son, David (b. 1931), with his first wife Marion Hill Beadle.^[5]

[ and  references">edit] Notes and  references

1. ^ Berg and  Singer, George Beadle: and  Uncommon Farmer, chapters 1-4
2. ^ Berg and  Singer, George Beadle: and  Uncommon Farmer, chapters 5-9
3. ^ Berg and  Singer, George Beadle: and  Uncommon Farmer, chapters 9-11
4. ^ Berg and  Singer, George Beadle: and  Uncommon Farmer, chapters 12-17
5. ^ Berg and  Singer, George Beadle: and  Uncommon Farmer, chapters 18-19

• Paul Berg and  Maxine Singer. George Beadle: an  Uncommon Farmer. The Emergence of Genetics in the 20th Century. Cold Springs Harbor Laboratory Press, 2003. ISBN 0-87969-688-5
• Nobel Lectures, Physiology or  Medicine 1942-1962, Elsevier Publishing Company, Amsterdam, 1964

[edit] External link

• Nobel biography

Preceded by Lawrence A. Kimpton

President of the University of Chicago 1961—1968

Succeeded by Edward H. Levi