No one invented DNA. It was discovered. Who exactly discovered it is up to interpretation. Gregor Mendel is the father of genetics because he figured out there was something that affected heredity. He used pea plants to test his theories. He mixed colors, heights, etc and observed the results. James Watson and Francis Crick have been officially credited with discovering the alpha helix formation of DNA. Watson and Crick received the Nobel Prize for their discovery in 1962.