Your investigation begins with the independent discoveries of genes and of DNA in the mid-1800s—which were not understood to be related for almost a century! Gregor Mendel, an Austrian monk, used pea plants to discover what discrete units of inheritance are, later called genes. Meanwhile, biochemist Friedrich Miescher extracted a sticky substance from the nuclei of cells later called DNA. Follow both trails into the 20th century, as chromosomes are discovered and the realization finally begins to dawn that genes and DNA may be related.