Well Darwin was pretty awesome, but he didn’t actually discover DNA. It was first discovered by a chemist called Meischer who called it ‘nuclein’. Darwin was still alive at that time, but it wasn’t worked out until after Darwin died that DNA was the hereditary material that carried genetic information. Oswald Avery was largely responsible for that discovery. Science often works that way: different people make discoveries at different times that add up together to explain how things work. That’s why communication of science is so important.