Cell differentiation is assayed indirectly by transplantation experiments. Cell differentiation may change during normal development. In mosaic eggs the potency of each blastomere is quickly limited to its fate. Mosaic eggs are characterized by twinning after blastomere separation. In regulatory eggs the potency of blastomeres is greater than their fate.
Regulatory eggs rely more on induction than mosaic eggs.
Local UV irradiation by itself has proven the existence of LCDs. Heterotopic transplantation can show that an LCD is necessary. Morphogenetic Movements a. Invagination is the transition of cells from an epithelial layer into an embryonic cavity. Delamination is the splitting of a sheet of cells into two parallel sheets. Convergent extension is the spreading movement of an epithelial sheet to cover a deeper layer of cells.