The discovery of DNA is very vital to back up Darwin’s theory.
Darwin’s theory was that species change with time (very slowly). He also came up with the theory of principle common descent which includes the thought that modern organisms have been produced through evolution, every new organism comes from pre-existing organisms, that each species has descended from other species, and that all species have shared a common ancestor. That theory can be supported by DNA and fossil records by multiple pieces of evidence. With fossils, the lower layers of rock are older, scientists can determine the source of changes in an organism based on the layers in the rock. Evidence for this theory also lays in the science of embryology as now we can see that many animals and human embryos look very similar which proves that we are all distantly related to common ancestors. DNA is used in the confirmation of Darwin’s theory as, when it was examined, it allowed enough variation to be considered new generations, and with that information, evolution is now understood as a process of changes in the frequencies of stable variants.