Break to build: fracture as a unifying morphogenetic strategy.

Fracture - the initiation and propagation of cracks - has long been associated with structural failure. However, active living tissues often harness fracture as a controlled morphogenetic tool due to their unique capacities to self-organise and self-repair. In this Review, we highlight how fractures are actively interpreted, integrated and functionalised within developmental programmes to sculpt tissues across scales and species. We connect core concepts from fracture mechanics, such as stress concentration, energy release and fatigue, to biological contexts, showing how tissues actively adapt these principles by remodelling their adhesion, cytoskeleton and extracellular matrix. From reversible epithelial tears to permanent organismal fission, we discuss examples in which fracture contributes to morphogenesis, homeostasis, reproduction and egress. Further, we argue for an interdisciplinary approach to understanding how fractures emerge and drive morphogenetic transitions.