Regeneration in Echinoderms: repair, regrowth, cloning

Regenerative potential is expressed to a maximum extent in echinoderms. It is a commonphenomenon in all the classes, extensively employed to reconstruct external appendages and internalorgans often subjected to amputation, self-induced or traumatic, rapidly followed by completesuccessful re-growth of the lost parts. Regeneration has been studied in adult individuals as well as inlarvae. In armed echinoderms, regeneration of arms is obviously frequent: in many cases, thedetached body fragments can undergo phenomena of partial or total regeneration independently of thedonor animal, and, in a few cases (asteroids), the individual autotomised arms can even regenerate toproduce new complete adults, offering superb examples of cloning strategies. In the species examinedso far most results throw light on aspects related to wound healing, growth, morphogenesis anddifferentiation, even though in most cases many crucial questions remain unanswered. The presentpaper provides an overview of the current understanding of the phenomenon and covers the mainbiological aspects of regeneration giving an idea of the “state of the art” across the phylum in terms ofexperimental approaches and representative models