Regeneration recapitulates many embryonic processes, including reuse of developmental regulatory regions

The wide distribution of regenerative capacity across the animal tree of life raises the question of how regeneration has evolved in distantly-related animals. Given that whole-body regeneration shares the same end-point - formation of a functional body plan - as embryonic development, it has been proposed that regeneration likely recapitulates developmental processes to some extent. Therefore, understanding how developmental processes are reactivated during regeneration is important for uncovering the evolutionary history of regeneration. Comparative transcriptomic studies in some species have revealed shared gene expression between development and regeneration, but it is not known whether these shared expression profiles correspond to shared functions, and which mechanisms activate expression of developmental genes during regeneration. We sought to address these questions using the acoel