George W. Beadle and Edward L. Tatum refined the concept of the gene to state which of the following original ideas?

a. one gene - one enzyme

b. one gene - one metabolic block

c. one gene - one transcript

d. one gene one polypeptide

e. one gene - one allele

one gene - one enzyme.

Explanation:

The Garrod's explain the hypothesis one gene enzyme and one enzyme. According to this hypothesis, the single gene codes for the single enzyme that plays an important role in the body metabolism.

The Garrod's hypothesis was experimentally performed by the George W. Beadle and Edward L. Tatum. They performed the biochemical studies and genetic tests on Neurospora to explain the one gene one enzyme hypothesis.

Thus, the correct answer is option (a).