Practice question

BMP pathway is major ventral regulator orchestrating apoptosis, mesoderm patterning, limb remodeling, dorsoventral neural specification. BMPs induce Id helix-loop-helix genes, regulate neural crest delamination via apoptosis through Msx2, posteriorize mesoderm, pattern limb interdigital death via BMPR1A-Smad1/5. Although BMP antagonists Noggin-Chordin establish dorsal-ventral polarity by creating low BMP zones permitting neural fate, BMP itself actively patterns polarity gradient as ventralizing signal. Some simplified curricula categorize primary functions as apoptosis and mesoderm excluding polarity terminology, defining that distractor as exception for assessment purposes, highlighting context-dependent nomenclature of axis patterning functions across species.