However, it is unclear how long in the 4-billion-year history of life DNA has performed this function, as it has been proposed that the earliest forms of life may have used RNA as their genetic material.
Det er dog uklart, hvor langt tilbage i livets fire milliarder år lange historie DNA har haft denne funktion, og det har været foreslået at de tidligste livsformer kan have anvendt RNA som deres genetiske materiale.