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#one gene-one enzyme hypothesis

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Beadle and Tatum performed their experiments on

Neurospora crassa red bread mold offered unique advantages: haploid vegetative mycelium exposing recessive mutations immediately without dominance masking, simple nutritional needs allowing prototrophic growth on minimal medium containing sucrose, mineral salts and biotin, and rapid sexual cycle permitting crosses and tetrad analysis. Beadle and Tatum exploited these features by irradiating conidia, culturing on complete medium then testing failure on minimal medium. Auxotrophs requiring arginine, nicotinamide or pyridoxine mapped blocks to single enzymes, demonstrating direct link between gen

Ref: Griffiths et al., Introduction to Genetic Analysis, 12th ed., Chapter 7: Neurospora as Model Organism Advantages

The concept of one gene–one enzyme hypothesis was proposed by

George Beadle and Edward Tatum in 1941 demonstrated gene-enzyme relationship by isolating nutritional mutants in haploid fungus through X-ray mutagenesis and nutritional screening. Exposing wild-type Neurospora to radiation and selecting survivors unable to grow on minimal medium unless supplemented with specific amino acids showed single-gene lesions abolish specific reactions. This established one-gene-one-enzyme hypothesis later refined to one-gene-one-polypeptide, founding biochemical genetics and bridging Mendelian transmission with metabolism. Their pioneering experiments earned 1958 Nob

Ref: Hartl & Ruvolo, Genetics, 6th ed., Chapter 14: Beadle and Tatum One-Gene-One-Enzyme Hypothesis