RESUMEN
Studies of regeneration research has a very profound historical background, longer than genetics and embryology per se. In this article, I have tried to make clear the importance of the discovery of Niazi on the effect of vitamin A on amphibian limb regeneration in the long tradition of regeneration study. His discovery is truly one of the main milestones in recent era of the field. It revitalized the study of regeneration, in particular the problem of replication of pattern. A more recent discovery of heteromorphic regeneration in tadpoles elicited by vitamin A by Mohanty-Hejmadi is also of a great historical significance. It has opened the way to investigate the most mysterious phenomena known from early 20th in modern eyes, most probably in terms of the epigenetic switch of homeotic genes.