Fig. 4. Hoxd10 expression in whole-mount embryos after transplantation of LS neural tube segments to T regions. On the left are schematics of the transplantation of donor LS segments (yellow) into T regions (blue). On the right are ventral views of experimental embryos at stages 30-31. In each case, transplanted LS segments had been positioned in a normal AP orientation. (A) Following transplantation of stage 15 donor LS segments into posterior T regions of a stage 14 host embryo, high Hoxd10 expression develops in the transplant region in accord with its LS origin. (B, C) Results were variable following transplantation of stage 13 donor LS segments into T regions of stage 12-13 host embryos. In a transplant placed in anterior T regions (B), Hoxd10 expression is only detected at the posterior end of the transplant and the level of expression is very low. In a transplant extending into posterior T regions (C), expression of Hoxd10 in the transplanted LS segments is equivalent to that in the host’s LS segments. Bars, 250 µm.