In the figure below (A, B) are the results of an experiment…
In the figure below (A, B) are the results of an experiment showing the effects of levels of Sonic hedgehog (Shh), secreted from notochord cells, on the differentiation of neurons in the intact neural tube. In panel C (right side), cells from chick neural tube were cultured in vitro in the presence of different concentrations of Shh, then immunostained for proteins characteristic of the different types of neurons shown in the picture (e.g. floor plate=FP, Motor, etc.). The left diagram in (C) shows the positions of cells that stain for these proteins in the normal intact neural tube. Based on the data shown in the figure (don’t worry about the details of the nervous system development!!), answer the questions below regarding how Shh is functioning to determine neural tube cell fates. D) Referring ONLY to panel B: is this a show it, move it, or lose it experiment? What is the conclusion? (Be careful not to OVER interpret. You only have the information in panel B) E) How does the experiment in panel C extend your conclusion noted in D) above?