Practice question

Vertebrate regeneration is not limited to embryonic stages but re-engages developmental programs via integrated genetic and cellular mechanisms operating asexually without gamete formation. It involves wound epidermis formation, immune modulation, dedifferentiation of mature cells into progenitors, activation of resident stem cells, and proliferation forming blastema or compensatory growth. Gene regulation is central: Wnt, FGF, BMP, Hedgehog, and retinoic acid pathways are redeployed with epigenetic remodeling and positional memory. This distinguishes regeneration from reproduction, which produces new organism, and explains why mammals regenerate liver and digit tips while salamanders regenerate whole limbs.