Fig. 9. The development of Hoxd10 expression in T segments bordered by LS paraxial mesoderm and LS segments transplanted to T regions with adjacent paraxial mesoderm. On the left are schematics of the surgical procedures. Whole-mount in situ hybridization was done at stages 28-29. On the right are ventral views of T and LS spinal regions. (A) Hoxd10 is not induced in the T spinal cord after placement of stage 13 anterior LS paraxial mesoderm into the T region of a stage 11 embryo. (B) Stage 13 LS neural tissue + its adjacent paraxial mesoderm was transposed to anterior T regions in a stage 11 host. Hoxd10 expression is low in transplanted neural segments as it is following transposition of LS neural tissue alone (see Fig. 4B). Only the most posterior transplant regions show expression above that in adjacent host regions. (C) No expression is induced in anterior T neural segments despite transplantation of stage 14 posterior LS paraxial mesoderm into anterior T regions at stage 11. Hoxd10 expression is visible in the transplanted mesoderm (see bracket). (D) Hoxd10 expression is also not induced in posterior T neural segments following an equivalent transplant of posterior LS paraxial mesoderm into posterior T regions. Again expression is visible in transplanted mesoderm. Bars, 250 µm.