Question

What happened when Spemann transplanted cells that were presumptive neural ectoderm to

the ventral side of an early gastrula? What did the transplanted cells become and what did this

show about cells in the early gastrula stage? Draw a diagram to help you explain

Answer 1

Ans: From 1903, Spemann conducted fundamental developmental biology work on newts in early gastrula and late gastrula stages. From his experiments now we come to know committed and non-committed cells. In early gastrula stage when he transplanted Presumptive neural ectoderm (from ventral side) from one newt embryo in to another embryo (on dorsal side), it normally becomes epidermis on dorsal side, and have only one neural plate on the ventral side, this shows that in early gastrula stage cells are uncommitted.

In late gastrula stage he repeated the above experiment and he found that instead of epidermis it has become neural plate and gastrula produced two neural plates on transplanted ventral and normal dorsal plates. This shows that in late gastrula stage cells are committed.