Fig. 8. Fate map of the DM. Schematic representation of the derivatives emanating from the different regions of the DM epithelium. All four lips (blue) give rise to myofibers as part of the second wave of myotome colonization that follows establishment of the early pioneer fibers. In addition, the rostral and caudal lips also generate the first mitotically active muscle progenitors that we termed `third wave' (Kahane et al., 2001) (PMP, red). The DM sheet (orange) dissociates and its progeny colonizes the two opposite anlage, the subectodermal space to give rise to dermis (yellow arrow) and the myotome to give rise to mitotic muscle progenitors (red arrow). Hence, the proliferating PMPs derive from two distinct sources: first from the rostral and caudal DM lips (Kahane et al., 2001) and later from the DM sheet (this paper).