(I) The relationship between genes and proteins was first proposed in 1909 when English physician A. Garrod suggested that genes dictate phenotypes through enzymes, the proteins that catalyze chemical processes in the cell. (II) The idea came from his observations of inherited diseases. (III) He hypothesized that an inherited disease reflects a body's inability to manufacture a particular enzyme, and he referred to such diseases as “inborn errors of metabolism”. (IV) The function of a gene is to dictate the production of a specific enzyme. (V) His hypothesis was ahead of its time but research conducted decades later by other scientists proved him right.