This document provides an overview of key concepts in developmental biology. It discusses induction, in which one cell or tissue signals another to influence developmental fate. Competence is the ability of a cell to respond to inductive signals through expression of receptors. Commitment is when a cell decides its fate, either through inductive signals or cytoplasmic determinants distributing asymmetrically. Specification is a reversible commitment, while determination is irreversible. Differentiation allows cells to become specialized through protein synthesis. Morphogenesis involves a cell gaining a particular shape. Autonomous and conditional specification are strategies where cells determine fate independently or through interactions, respectively.

1. BASICS OF DEVELOPMENTAL
BIOLOGY
DR. GHIZAL FATIMA
ASSOCIATE PROFESSOR
ERA UNIVERSITY LUCKNOW

2. INDUCTION
• Refers to cascade of signaling events, during which a
cell or tissue signals to another cell or tissue to
influence its developmental fate.
• Signals that gets generated is called inductive signals
• The inductive signals can be proteing, growth and
differentiation factor
• There are 2 components in every inductive interaction-
• A-Inducer-tissue or cell that produce signal
• B- Responder

3. Competence
• The ability to respond to a specific inductive
signal is called as Competence.
• It occur through expression of appropriate
receptor or component of signaling pathway.
• Best eg. is development of eye

4. Commitment
• The commitment of a cell to specific cell fate
and their capacity to diffentiate into perticular
type of cells.
• Commitment: deciding the fate of a cell
• Cell can attain commitment by:
• 1-cytoplasmic determinant
• 2- Inductive signals
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5. Cytoplasmic determinant
• A cell can devide into 2 daughter cell with
different fate.
• This can be achieved by asymmetric
distribution of cytoplasmic factor (RNA,
Protein) that can regulate fate
• They act in early development

6. Cell fate
• The fate of cell to generate in all the different
cell types it forms during normal development
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HEART LUNGS KIDNEY
FATE

7. Commitment
• Deciding fate of cell
• Cell fate describes the range of cell types a
particular cell forms during normal
development
• Stages of commitment
• 1-specification
• 2-determination

8. Specifation
• It is a labile phase, so it is not fixed
• It can be revert from its fate.
• So in this case commitment is reversible
• It is capable of differentiating autonomously
when placed in a neutral environment.

9. Determination
• Here in this case commitment is fixed.
• It is not going to revert from its fate, so
commitment is irreversible.

10. Differentiation
• Cell differntiation is the process by which cells
becomes funtionally specialized.
• Allowing formation of distinct cell types.
• Structural and functional specificity of cell
depends on proteins it synthesizes.

11. Morphogenesis
• Gaining a particular shape

12. Cell types specification and their
characterstics
• During specification there are 3 major
strategies that embryo can exhibit
• 1-autonomous specification
• 2- conditional specification
• 3-syncytial specification (insects)

13. Autonomous specification
• In most invertibrates
• Knows very early what it is to become without
interacting with other cells
• Prospective potency is equal to prospective
fate
• Produces mosac determinative development

14. Conditional specification
• Characteristic of all invertebrates and few
vertebrates
• It’s a process by which cells achieve there
respective fate by interaction with other cells.
• Here what a cell has to become is specified by
the array of interactions. It has with its
neighbors, which include cell to cell contact.
• Prospective potency is greater than
prospective fate