Fig. 7. The development of regional character in T neural segments following transplantation into LS regions. Shown at top is a schematic of the transplant surgery. (A) Ventral view of the posterior spinal cord from a stage 29 experimental embryo. Stage 11 T segments had been placed in the LS region of a stage 13 host embryo. Hoxd10 expression is high in host LS segments, anterior and posterior to the T transplant, but low in donor T segments. Only the most posterior end of the transplant shows slight expression. (B-G) Sections from a stage 28 embryo in which transplanted T segments show higher levels of Hoxd10 expression. In this case, stage 13 donor T segments had been placed into the LS region of a stage 13 host. The axial level of placement was similar to that of the embryo shown in A. Hoxd10 expression patterns and LIM patterns (Isl1/2 and Lim1/2) are T-like in anterior transplant regions (B-D) but largely LS-like in posterior transplant regions (E-G). Bars, 250 µm.