Question: The DNA of living organisms, does it provide results and knowledge in differnt sections of scientific knowledge?

Nick Goldman answered on 7 Mar 2014:

It certainly does. For example, by comparing the DNA of different organisms we can work out which ones are closely related (like humans and chimpanzees) and which ones are only distant relatives (like mice and fish). So, there DNA is telling us about historical relationships: the evolutionary tree, or “phylogeny”.
Then, by looking at which parts of organisms’ DNA changes the most we can learn about what its function is. A part of the genome that changes (“evolves”) quickly is often not so important; parts that evolve slowly are often the ones that are crucial to keeping the organism alive.
And it also tells us something to look at what sort of changes happen in DNA. In some genes, the only changes are ones which we know won’t make much difference to how a gene works. In other genes, we see changes which look like they have a big effect. This helps us work out whether the gene is one which (for example) is important in the way your body reacts to disease.