Ephrin is normally expressed in the caudal/posterior half of…

Ephrin is normally expressed in the caudal/posterior half of each somite, and neural crest migrates specifically through the rostral/anterior half of somites. If you generated a mouse that overexpresses the Ephrin gene in somites, as shown below, you would expect the neural crest  __________ . Pick the best ending for this sentence.

One of your colleagues shows you these images of cross-secti…

One of your colleagues shows you these images of cross-sections from control (A) and mutant (B) E10.5 mouse embryos with a dotted line surrounding the DRG. The sections were incubated with a probe that labels activated Caspases (the dark product). Deletion of which gene would most likely result in the relative increase in caspase activation seen in the mutant DRG in B?