Practice question

The transition from conditional to autonomous development during gastrulation was elegantly shown by transplantation experiments in newt embryos. Prospective ectoderm fragments from early gastrula transplanted into regions fated to become endoderm changed fate to match host location, indicating continued responsiveness to surrounding inductive cues and regulative potential. Identical grafts taken from late gastrula, however, differentiated according to donor origin, forming epidermis even within gut environment, demonstrating acquired autonomous determination. This temporal progression reveals how cumulative signaling, community effects and chromatin restriction progressively narrow potency, converting plastic specification into locked determination.