What is the purpose of DNA?

Actually, DNA makes you who you are. It has all your heredity info, like your hair color, your personality, etc. No two person's DNA is the similar, not even twins

The major role of DNA is to store information over long periods without any important loss of information contained in it. It is the precursor for all the metabolic reactions taking place in our body (involved might be directly or indirectly). DNA is so important because it does lot of things to say if you were found dead with no ID or anything they could use your DNA to figure out who you were, DNA is your individuality, and it confirms the colors and shapes of what makes up you. It also illustrate if you have any diseases like hemophilia.