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George Beadle & Gene Function
Of the pioneers of modern genetics, George Beadle is considered to be one of the most significant contributors to the understanding of genetics. His pioneering work on the bread mold Neurospora Crassa helped decipher the first draft of how genes function. Beadle, along with Edward Tatum, developed the “One Gene One Enzyme" concept. It was a significant advancement in genetics, although it has has since been modified and improved upon. For this important finding, both Beadle and Tatum, along with Joshua Lederberg (who worked on the findings of Beadle & Tatum in respect to gene transfer in bacteria), were awarded the Nobel prize for Physiology or Medicine in 1958.
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Early Life of George Beadle
George Beadle was born in Wahoo, Nebraska in 1903. Born into an agricultural family, he had a life long interest in agriculture and in his early years enrolled in agriculture courses at the University of Nebraska with the intention of becoming a farmer himself. At the urging of his professor, he he switched to serious research. Working on Zea Mays, he eventually obtained his PhD degree. Beadle received a research fellowship to continue at the California Institute of Technology with pioneers such as Th.Dobzhansky on crossing-over in the fruit fly Drosophila melanogaster. At Caltech he studied under another Nobel laureate, Thomas Morgan, and collaborated with another, Barbara McClintock, during his stay at Cornell.
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"One Gene one Enzyme" Concept
Known to his friends as “Beets", he met Edward Tatum during a trip to Paris and later paired up with him at Stanford to work on the bread mold Neurospora crassa. The duo set out to see whether a previously proposed concept by English physician Archibald Garrod could be proved experimentally. Garrod proposed that a specific gene is responsible for the production of a protein. Using Neurospora crassa exposed to x-rays, thereby inducing mutations, they isolated mutants that were deficient for a single protein which made them incapable of carrying out enzymatic reactions for metabolizing a particular nutrient. By genetic analysis, they were able to show that the loss of the protein/enzyme was due to a mutation in one particular gene that was responsible for the protein, thereby proving Garrod’s idea of “One Gene One Enzyme."
Although today we know that the concept proposed by Beadle and Tatum does have some exceptions and their finding would more accurately be titled “One Gene One Polypeptide", their findings laid the foundations for progress in the development of additional genetic discoveries.
Suggested Reading: http://www.accessexcellence.org/RC/AB/BC/One_Gene_One_Enzyme.php