one gene/one enzyme hypothesis, a general rule, proposed in 1941 by G. Beadle and E. Tatum, that each gene in a chromosome controls the synthesis of one enzyme. A modification of this idea, the one gene/one polypeptide hypothesis, accommodates the fact that all gene products are polypeptides but not all polypeptides are enzymes. A further modification, the one cistron/one polypeptide concept, accommodates alternate splicing and alternative promoter sequences.
