What conclusion was drawn from Beadle and Tatum's experiment with mutant bread mold?

Beadle and Tatum's experiment with mutant bread mold led to the conclusion that genes code for proteins, which is a fundamental principle in genetics. They conducted a series of experiments on the mold Neurospora crassa by exposing it to X-rays, which induced mutations. By observing the growth of these mutant strains on minimal media (which contained only basic nutrients), they discovered that each mutant could not grow unless specific nutrients were added. This indicated that the mutations affected specific biochemical pathways, ultimately linking genes to the production of enzymes and proteins responsible for those metabolic processes. Therefore, the conclusion that "genes code for proteins" underscores the role of genes in determining physiological traits and functions at the molecular level, establishing the foundation for the one gene-one enzyme hypothesis. This relationship is critical for understanding how the genetic information is translated into functional products in living organisms.