JC- SPEMANN AND MANGOLD EXPERIMENT AND CONCLUSIONS

Question 1

What did the concept of embryonic induction, discovered by Spemann & Mangold, do?

Answer 1

It paved the fundamental aspects of how tissues and organs develop in embroys

Question 2

What did they demonstrate by doing this?

Answer 2

That the pattern of developing cells are influenced by the activity of surrounding cells.

Question 3

How did they perform the study?

Answer 3

1. They used new amphibian embryos.
2. Cut out tissue from dorsal blastopore lip of the presumptive notochord, transplanted this into the ventral side of the donor embryo, at the presumptive endoderm.

Question 4

What did the transplantation do?

Answer 4

It initiated the second gastrulation process of surrounding tissue in the donor embryo.

Question 5

What did the transplanted tissue become and what was its function?

Answer 5

The transplanted dorsal blastopore lip became the ORGANISER and directed the development of cells surrounding it.

Question 6

What did the organiser produce and what are they specialised to do?

Answer 6

The organiser produces BMP inhibitors, CHORDIN AND NOGGIN. These are required for neural induction in which they control the fate of neighbouring cells.
They are also involved in the specification of the dorsal mesodermal and anterior endodermal fates

Question 7

Name the 3 parts of the early amphibian dorsal lip blastopore

Answer 7

1. Presumptive Notochord
2. Presumptive Somite’s
3. Presumptive Endoderm

Question 8

What were the main conclusions of the study?

Answer 8

1. The organiser (Dorsal Blastopore Lip) in early amphibian embryos is capable of influencing neighbouring cells to direct their development.
2. The study proves induction and plasticity of development
3. Transplantation of dorsal blastopore lip (ORGANISER) enables the 2nd gastrulation process.
4. Dorsal blastopore lip acts as the gastrulation organiser and signals to adjacent tissues

Question 9

What is plasticity?

Answer 9

Plasticity is when cells can alter their fate due to exposure to signals (external and internal).