Reversion, in evolutionary biology it is the return of a character to one of its previous ancestral states. Reversion is quite commonly observed within DNA. The existence of reversion refutes Dollo's law a 19th century theory that evolution cannot return to a prior form of an organism. Similarly, in horticulture, a reversion is when a plant or branch of a specific cultivar, such as a dwarf, returns to the growth pattern of the parent variety. Image:Mantell's Iguanodon restoration.jpg This article is a . You can help My English Wiki by expanding it.