Sinh học - Chapter 17: From gene to protein

One type of mutant required only the addition of arginine to the minimal growth medium. Beadle and Tatum concluded that this mutant was defective somewhere in the biochemical pathway that normally synthesizes arginine. They identified three classes of arginine-deficient mutants, each apparently lacking a key enzyme at a different step in the synthesis of arginine. They demonstrated this by growing these mutant strains in media that provided different intermediate molecules. Their results provided strong evidence for the onegene - one enzyme hypothesis.