FIG. 2.

Postnatal bone healing recapitulates processes of bone formation in utero. Mesenchymal condensation is a seminal event marking the initiation of skeletogenesis (blue dotted square in schematic). By tracking relative gene expression, one can assess the relative stage and/or path of lineage commitment for uncommitted pluripotent cell-like periosteum-derived cells. Red font depicts gene markers for pre-, peri-, and postmesenchymal condensation. Magenta font indicates gene markers for the formation of cell–cell and cell–matrix adhesions, key for self-aggregation of cells and emergent tissue architecture. Mesenchymal stem cells can commit to chondrogenic (orange), osteogenic (blue), and adipogenic (green) path lineages. Figure adapted and used with permission.³⁹ Color images available online at www.liebertpub.com/teb