Fig. 3. Transplant of somitic and presomitic tissue to replace the DML. (A-F) Confocal z-series of transplanted embryos immunolabelled for desmin (red) and quail (green). (A,B) Transplant of the dermomyotome sheet (Table 1, 4.01). (A) Composite through the myotome region shows dorsomedial expansion of the transplanted tissue and centrally aligned nuclei in quail derived myotome (arrow). The arrowheads indicate the level of the DML ablation. An epithelial DML has reformed at the correct position and is composed of quail cells. (B) The desmin immunoreactivity of A showing the medially located, donor-derived, myotome has grown to a similar extent as its neighbours. (C,D) Transplant of the VLL (Table 1, 5.02). (C) A single optical section in the plane of the myotome of the operated somite shows quail nuclei associated with donor derived myotome. The transplanted tissue has remained within the segment boundaries, a few cells at the medial limit have extended past the segment boundaries. In this example, quail myocyte nuclei (arrows) are not centrally localised but spread along the axial myotome length. (D) The desmin channel of C. The growth of the donor myotome is consistent with that of neighbours (bar) and an epithelial DML structure is evident in the correct location. (E,F) Transplant of caudal PSM (Table 1, 6.06). (E) The quail tissue has expanded in concert with the neighbouring somites and formed a DML. (F) The desmin channel of E highlights the DML structure and shows myofibres situated just lateral to the DML. There is a gap (bar) between the host and the older, laterally situated, donor myofibres (arrows). Donor fibres correspond to the axial length of the transplanted fragment.