Who needs stem cells if you can dedifferentiate?

Regenerative mechanisms involving either stem cell differentiation or dedifferentiation of mature cells have been described in various systems, but the relationship between such disparate mechanisms is unclear. Two recent papers, one by Sandoval-Guzmán et al. (2013) and one by Tata et al. (2013), address fundamental questions about the universality of reparative regeneration and whether mammals share any properties seen in lower vertebrates.