Chapter 24 Outline

Defining The Problem of Regeneration

• What is required for regeneration?
• Modes of regeneration

Regeneration, a Recapitulation of Embryonic Development?

An Evolutionary Perspective on Regeneration

Plants and animals: Different lifestyles, different regenerative potentials

• Why are so many animals unable to regenerate?

Plant Regeneration

• A totipotent way of regenerating
• Regeneration by a single cell for a single cell
• Regeneration by a single cell for a whole plant
• A stem’s stem cell

Whole Body Animal Regeneration

• Stem cell-mediated regeneration, morphallaxis, and epimorphosis in hydra
• Routine cell replacement by three types of stem cells
• The head activator
• The hypostome as organizer
• A gradient of Wnt3 is the inducer
• Morphallaxis and epimorphosis in hydra regeneration
• Stem cell-mediated regeneration in flatworms
• The blastema and adult pluripotent stem cells
• Head-to-tail polarity
• A morphological memory map flexes its PCG muscles

Tissue-Restricted Animal Regeneration

• Salamanders: Epimorphic limb regeneration
• Dedifferentiation and stem cell activation
• Fates restricted
• Nerves and the apical epidermal cap
• Eye of newt: A “clear” argument for transdifferentiation
• Luring the mechanisms of regeneration from zebrafish organs
• Wnt upon a fin

Regeneration in Mammals

• Compensatory regeneration in the mammalian liver
• The spiny mouse, at the tipping point between scar and regeneration