Practice question

Fate mapping using DiI labeling of chick primitive streak reveals anterior-posterior regionalization: Hensen's node contributes notochord and prechordal plate head mesoderm expressing Goosecoid, anterior streak forms paraxial somitic mesoderm, middle forms intermediate mesoderm, posterior streak contributes lateral plate and extraembryonic mesoderm. Posterior epiblast exposed to high BMP4 and Wnt8 signals activates lateral plate markers FoxF1 and promotes vascularization. Posterior ingressing cells split into somatic and splanchnic layers generating body wall, limbs and yolk sac vasculature guided by FGF and BMP gradients.