DNA, RNA, and Chromosomes

What is the one gene–one enzyme hypothesis?

In the 1930s, George Beadle (1903–1989) and Boris Ephrussi (1901–1979) theorized that the variety of fruit fly mutations might be due to mutations of individual genes that code for each of the enzymes involved in a given pathway. Subsequently, Beadle and Edward Tatum (1909–1975) performed a series of experiments with the orange bread mold Neurospora that elucidated the enzymatic pathway required by the fungus to produce a specific nutritional requirement, arginine. The researchers were able to create a series of mutants, each lacking in a different enzyme in the pathway. In this way they were able to piece together the sequence of events required for the production of arginine and thereby show where each mutant fit. The work of Beadle and Tatum provided important support for the one gene one enzyme hypothesis, which holds that the function of a gene is to produce a specific enzyme. Their work garnered a Nobel Prize in Physiology or Medicine in 1958.


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