One gene - one enzyme hypothesis

The one gene - one enzyme hypothesis was postulated by George Beadle and Edward Tatum in 1941. This hypothesis was a significant contribution to the field of genetics and laid the foundation for the understanding of how genes control the production of specific enzymes.

Explanation:

Introduction to the one gene - one enzyme hypothesis

The one gene - one enzyme hypothesis suggests that each gene is responsible for the production of a specific enzyme. Enzymes are proteins that catalyze biochemical reactions in the body. Beadle and Tatum proposed this hypothesis based on their studies on the bread mold Neurospora crassa.

Experimental evidence

To test their hypothesis, Beadle and Tatum exposed Neurospora crassa to X-rays, which caused mutations in its genes. They then observed the effects of these mutations on the growth of the mold. They found that certain mutations resulted in the inability of the mold to grow on a minimal medium, which contained only essential nutrients.

Complementation analysis

Beadle and Tatum performed complementation analysis to further support their hypothesis. They crossed different mutants of Neurospora crassa with each other and observed the growth of the resulting offspring. If two mutants complemented each other, meaning that their offspring could grow on a minimal medium, it suggested that the mutations affected different genes. However, if the offspring could not grow on a minimal medium, it suggested that the mutations affected the same gene.

Conclusion

Based on their experiments, Beadle and Tatum concluded that each gene is responsible for the production of a specific enzyme. This hypothesis revolutionized the understanding of genetic control of biochemical pathways and provided a link between genes and proteins. It laid the foundation for the field of molecular biology and paved the way for further research on the relationship between genes and enzymes.

Therefore, the correct answer is option C, Beadle and Tatum.