Скачать или смотреть Embryonic induction | Speman | Mangold | NBF | FBISE | Class 12

#biology #fbise #federalboard #science #bioclass #faisalabadboard #class12 #developmentbiology #kpkboard #balochistanboard

Experiment: Embryonic Induction by Spemann and Mangold (1924)

Objective: Investigate the role of tissue interactions in embryonic development.

Model Organism: Newt embryo (Triturus cristatus).

Methodology:

1. Spemann and Mangold isolated the dorsal blastopore lip (DBL) from a newt embryo.
2. They transplanted the DBL into a secondary embryo, creating a host- graft combination.
3. The host embryo was then allowed to develop.

Key Findings:

1. The transplanted DBL induced the formation of a secondary neural axis, including a brain, spinal cord, and eyes.
2. The induced tissues originated from the host embryo, not the transplanted DBL.
3. The orientation of the induced neural axis was determined by the host embryo's existing tissue layers.

Conclusion:

Spemann and Mangold's experiment demonstrated:

1. Embryonic induction: The ability of one tissue to influence the developmental fate of adjacent tissues.
2. Organizer tissue: The DBL acts as an organizer, directing the development of surrounding tissues.
3. Tissue interaction: Cell-cell interactions play a crucial role in shaping embryonic development.

Impact:

1. Challenged preformationism and supported epigenesis.
2. Established the concept of embryonic induction.
3. Laid groundwork for understanding tissue interactions and pattern formation in development.

Awards and Recognition:

Hans Spemann was awarded the Nobel Prize in Physiology or Medicine in 1935 for his discovery of embryonic induction.

Follow-up Research:

Spemann's work inspired further research on:

1. Neural induction
2. Mesoderm induction
3. Limb formation
4. Tissue interactions and signaling pathways

Key Concepts:

1. Embryonic induction
2. Organizer tissue
3. Tissue interaction
4. Pattern formation
5. Neural axis formation

Important Figures:

1. Hans Spemann
2. Hilde Mangold (collaborator and spouse)