In most regenerating systems, blastema cells arise by dedifferentiation of functional tissue cells. In is still debatable whether dedifferentiated cells or a undifferentiated cells, the neoblasts, are the main cells. Moreover, it is unclear whether in the intact neoblasts are quiescent cells ‘reserved’ for serve as functional stem cells of all differentiated uncertainties partly stem from the failure to conventional labelling methods neoblasts from Here we describe a new approach to these problems regenerative and stem cell capabilities of purified differentiated cells when introduced, separately, into hosts. Introduction of neoblasts led to resumed blastema formation, and extended or complete survival differentiated cells, in contrast, never did so. neoblasts can be qualified as totipotent stem cells of blastema cells, while dedifferentiation does not either in intact or regenerating organisms. In strengthen the idea that different types of formation, linked to the tissular complexity of the present in the animal kingdom.