One Gene-one polypeptide was given by

One Gene-one polypeptide was given by Beadle.
The theory is that each gene is responsible for the synthesis of a single polypeptide. It was originally stated as the one gene-one enzyme hypothesis by the US geneticist George Beadle in 1945 but later modified when it was realized that genes also encoded non-enzyme proteins and individual polypeptide chains.
It means that some genes accounted for single polypeptide chains of a protein comprised of multiple chains. The phenomena led scientists to conclude that genes specify protein products.