CSIR-NET LIFE SCIENCES

Unit 5: Developmental Biology

Complete Topic-Wise Syllabus

Development • Gametogenesis • Fertilization • Embryogenesis • Morphogenesis • Organogenesis • Plant Development • Aging

A. Basic Concepts of Development

🧬 1. Basic Principles of Development

• Developmental biology and its scope
• Embryonic development
• Post-embryonic development
• Cell proliferation
• Cell differentiation
• Cell migration
• Cell-cell interactions
• Cell-matrix interactions

🔬 2. Potency

• Definition of developmental potency
• Totipotency
• Pluripotency
• Multipotency
• Oligopotency
• Unipotency
• Relationship between potency and differentiation

🎯 3. Commitment

• Developmental commitment
• Specification
• Determination
• Commitment versus differentiation
• Reversible and irreversible developmental decisions

🧪 4. Specification

• Autonomous specification
• Conditional specification
• Syncytial specification
• Role of cell-cell interactions

🔗 5. Induction

• Inductive interactions
• Inducer and responder tissues
• Primary induction
• Secondary induction
• Reciprocal induction
• Competence of responding cells

🧬 6. Competence

• Definition of competence
• Competent responding cells
• Receptor expression
• Signal-dependent competence
• Developmental competence

🔒 7. Determination

• Commitment of cell fate
• Determined cells
• Irreversible developmental commitment
• Relationship between determination and differentiation

🌱 8. Differentiation

• Cell specialization
• Changes in gene expression
• Tissue-specific gene expression
• Terminal differentiation
• Dedifferentiation
• Transdifferentiation

🌈 9. Morphogenetic Gradients

• Morphogens
• Concentration gradients
• Threshold responses
• Positional information
• Pattern formation
• French flag model
• Examples of morphogen signaling

🧬 10. Cell Fate and Cell Lineages

• Cell fate determination
• Cell lineage
• Lineage tracing
• Developmental potential
• Asymmetric cell division
• Stem cell lineages

🌟 11. Stem Cells

• Embryonic stem cells
• Adult stem cells
• Induced pluripotent stem cells
• Stem cell self-renewal
• Stem cell differentiation
• Stem cell niches
• Therapeutic applications

🧬 12. Genomic Equivalence

• Concept of genomic equivalence
• Same genome in differentiated cells
• Differential gene expression
• Nuclear transplantation experiments
• Somatic cell nuclear transfer

🥚 13. Cytoplasmic Determinants

• Maternal factors
• Localized cytoplasmic determinants
• Asymmetric distribution of molecules
• Maternal mRNAs
• Maternal proteins
• Role in early embryonic development

🧬 14. Genomic Imprinting

• Parent-of-origin-specific gene expression
• Maternal imprinting
• Paternal imprinting
• DNA methylation
• Epigenetic regulation
• Imprinted genes

🧪 15. Mutants in Developmental Biology

• Loss-of-function mutations
• Gain-of-function mutations
• Conditional mutants
• Maternal-effect mutants
• Developmental mutant analysis

🧬 16. Transgenic Organisms

• Transgene introduction
• Gene expression analysis
• Reporter genes
• Knockout organisms
• Knock-in organisms
• Transgenic model organisms

🎯 CSIR-NET Core Sequence:

Potency → Specification → Determination → Differentiation
Induction → Competence → Cell fate → Tissue organization
Morphogen gradient → Positional information → Pattern formation

B. Gametogenesis, Fertilization and Early Development

♂️ 1. Spermatogenesis

• Formation of sperm
• Spermatogonia
• Primary spermatocytes
• Secondary spermatocytes
• Spermatids
• Spermatozoa
• Meiosis during gametogenesis
• Spermiogenesis

♀️ 2. Oogenesis

• Formation of female gametes
• Oogonia
• Primary oocytes
• Secondary oocyte
• Ovum
• Meiosis in oogenesis
• Polar body formation

🧬 3. Sperm-Egg Recognition

• Sperm-egg interaction
• Species-specific recognition
• Sperm surface proteins
• Egg surface receptors
• Zona pellucida
• Acrosome reaction
• Sperm binding and penetration

🥚 4. Fertilization

• Sperm activation
• Acrosome reaction
• Sperm-egg fusion
• Oocyte activation
• Calcium signaling
• Cortical reaction
• Block to polyspermy
• Pronuclear formation
• Zygote formation

🔬 5. Cleavage

• Definition of cleavage
• Rapid mitotic divisions
• Blastomeres
• Holoblastic cleavage
• Meroblastic cleavage
• Radial cleavage
• Spiral cleavage
• Determinate cleavage
• Indeterminate cleavage

🟢 6. Blastula Formation

• Morula
• Blastula
• Blastocoel
• Blastocyst
• Inner cell mass
• Trophoblast

🌐 7. Embryonic Fields

• Developmental fields
• Organizing regions
• Positional information
• Embryonic induction
• Field interactions

🌀 8. Gastrulation

• Reorganization of embryonic cells
• Formation of germ layers
• Invagination
• Involution
• Ingression
• Delamination
• Epiboly

🧬 9. Germ Layers

• Ectoderm
• Mesoderm
• Endoderm
• Derivatives of ectoderm
• Derivatives of mesoderm
• Derivatives of endoderm

🐣 Animal Development Sequence:

Gamete formation → Fertilization → Zygote → Cleavage → Morula → Blastula → Gastrulation → Germ-layer formation → Organogenesis

🌱 10. Male Gametophyte Development in Plants

• Microsporogenesis
• Microspore mother cell
• Meiosis
• Microspore tetrad
• Pollen grain formation
• Vegetative cell
• Generative cell
• Pollen tube development

🌸 11. Embryo Sac Development

• Megasporogenesis
• Megaspore mother cell
• Megaspore formation
• Functional megaspore
• Female gametophyte
• Egg apparatus
• Synergids
• Central cell
• Antipodal cells

🌼 12. Double Fertilization

• Syngamy
• Triple fusion
• Zygote formation
• Endosperm formation
• Diploid embryo
• Triploid endosperm

🌱 13. Plant Embryogenesis

• Zygote division
• Proembryo
• Globular stage
• Heart stage
• Torpedo stage
• Mature embryo

↔️ 14. Establishment of Symmetry in Plants

• Apical-basal axis
• Radial symmetry
• Bilateral symmetry
• Polarity
• Auxin distribution
• Positional information

🌾 15. Seed Formation

• Embryo development
• Endosperm development
• Seed coat formation
• Seed maturation
• Seed dormancy
• Storage reserves

🌱 16. Embryo and Endosperm Development

• Embryonic pattern formation
• Endosperm cellularization
• Maternal-paternal contributions
• Nutrient transfer
• Seed maturation

🌱 17. Seed Germination

• Water imbibition
• Activation of metabolism
• Mobilization of stored reserves
• Radicle emergence
• Seedling development
• Role of gibberellins
• Role of abscisic acid

🌿 Plant Development Core:

Microsporogenesis → Pollen development
Megasporogenesis → Embryo sac formation
Syngamy + Triple fusion → Double fertilization
Embryogenesis → Seed formation → Germination

C. Morphogenesis and Organogenesis in Animals

🦠 1. Dictyostelium Development

• Cell aggregation
• Cell differentiation
• cAMP signaling
• Slug formation
• Fruiting body formation
• Social amoeba development

🪰 2. Drosophila Development

• Early embryogenesis
• Maternal-effect genes
• Anterior-posterior axis
• Dorsal-ventral axis
• Segmentation genes
• Gap genes
• Pair-rule genes
• Segment polarity genes
• Homeotic genes
• Hox genes

🧬 3. Drosophila Axis Formation

• Bicoid
• Nanos
• Dorsal
• Caudal
• Morphogen gradients
• Maternal determinants

🎯 Drosophila High-Yield:
Maternal effect genes → Gap genes → Pair-rule genes → Segment polarity genes → Hox genes

🐸 4. Amphibian Development

• Fertilization
• Cortical rotation
• Cleavage
• Blastula
• Gastrulation
• Neurulation
• Mesoderm induction
• Spemann organizer
• Nieuwkoop center

🐣 5. Chick Development

• Blastoderm
• Primitive streak
• Gastrulation
• Hensen's node
• Somite formation
• Neural tube formation
• Organ development

🪱 6. Vulva Formation in Caenorhabditis elegans

• Cell-cell signaling
• LIN-3 signaling
• EGF receptor
• Ras pathway
• Vulval precursor cells
• Inductive signaling
• Cell fate determination

👁️ 7. Eye Lens Induction

• Inductive interactions
• Optic vesicle
• Surface ectoderm
• Lens placode
• Lens vesicle
• Reciprocal induction

🦵 8. Limb Development

• Limb bud formation
• Apical ectodermal ridge
• Zone of polarizing activity
• FGF signaling
• Shh signaling
• Proximal-distal patterning
• Anterior-posterior patterning
• Dorsal-ventral patterning

♻️ 9. Limb Regeneration

• Regeneration mechanisms
• Blastema formation
• Cell proliferation
• Positional information
• Tissue pattern restoration

🧠 10. Neuronal Differentiation

• Neural progenitor cells
• Neurogenesis
• Neuronal migration
• Axon growth
• Dendrite formation
• Synapse formation
• Neuronal differentiation

🐛 11. Post-Embryonic Development

• Larval development
• Juvenile stages
• Metamorphosis
• Hormonal regulation
• Juvenile hormone
• Ecdysone

🌍 12. Environmental Regulation of Development

• Temperature
• Nutrition
• Light
• Hormonal signals
• Environmental stress
• Phenotypic plasticity
• Epigenetic responses

♂️♀️ 13. Sex Determination

• Chromosomal sex determination
• XX-XY system
• ZZ-ZW system
• XO system
• Environmental sex determination
• Temperature-dependent sex determination
• SRY gene
• Sex differentiation pathways

🧠 Important Developmental Principle:

Morphogenesis = formation of body shape and organization.
Organogenesis = formation of organs from embryonic tissues.
Differentiation = specialization of cells.
Induction = one tissue influences the developmental fate of another.

D. Morphogenesis and Organogenesis in Plants

🌱 1. Shoot Apical Meristem

• Organization of shoot apical meristem
• Stem cell niche
• Central zone
• Peripheral zone
• Rib zone
• Stem cell maintenance
• WUSCHEL signaling
• CLAVATA signaling

🌱 2. Root Apical Meristem

• Root stem cell niche
• Quiescent center
• Root cap
• Meristematic zone
• Elongation zone
• Differentiation zone
• Auxin gradient

🌿 3. Shoot Development

• Shoot meristem activity
• Cell division
• Cell expansion
• Cell differentiation
• Vascular development
• Branch formation

🌱 4. Root Development

• Root meristem
• Lateral root initiation
• Lateral root development
• Root hairs
• Auxin-mediated patterning
• Root vascular differentiation

🍃 5. Leaf Development

• Leaf primordium formation
• Leaf polarity
• Adaxial-abaxial patterning
• Leaf expansion
• Leaf differentiation
• Vein formation

🌿 6. Phyllotaxy

• Arrangement of leaves on the stem
• Alternate phyllotaxy
• Opposite phyllotaxy
• Whorled phyllotaxy
• Auxin distribution
• Phyllotactic pattern formation

🌸 7. Transition to Flowering

• Vegetative phase
• Reproductive phase
• Photoperiodism
• Vernalization
• Florigen
• FT protein
• Gibberellins
• Autonomous flowering pathway

🌼 8. Floral Meristem

• Floral meristem identity
• Floral organ initiation
• APETALA genes
• LEAFY
• Floral meristem determinacy

🌸 9. Floral Organogenesis

• Sepals
• Petals
• Stamens
• Carpels
• Floral organ identity
• Organ patterning

🧬 10. ABC Model of Flower Development

• A-class genes
• B-class genes
• C-class genes
• Sepal identity
• Petal identity
• Stamen identity
• Carpel identity

🌸 ABC Model – Quick Revision

A → Sepals
A + B → Petals
B + C → Stamens
C → Carpels

🌱 11. Plant Hormones in Development

• Auxin
• Cytokinin
• Gibberellin
• Abscisic acid
• Ethylene
• Strigolactones
• Hormonal crosstalk

E. Programmed Cell Death, Aging and Senescence

☠️ 1. Programmed Cell Death

• Programmed cell death as a developmental process
• Apoptosis
• Necroptosis
• Autophagy-associated cell death
• Developmental cell elimination

🔴 2. Apoptosis

• Intrinsic pathway
• Extrinsic pathway
• Mitochondrial pathway
• Caspases
• Cytochrome c
• Apoptosome
• Death receptors
• Fas-FasL pathway
• DNA fragmentation
• Cell shrinkage
• Apoptotic bodies

🧬 3. Regulation of Apoptosis

• Bcl-2 family proteins
• Pro-apoptotic proteins
• Anti-apoptotic proteins
• p53
• Caspase activation
• Inhibitors of apoptosis proteins

♻️ 4. Autophagy

• Macroautophagy
• Microautophagy
• Chaperone-mediated autophagy
• Autophagosome
• Lysosomal degradation
• Cellular recycling
• Autophagy in development

⏳ 5. Aging

• Biological aging
• Cellular aging
• Genomic instability
• Telomere shortening
• Epigenetic alterations
• Mitochondrial dysfunction
• Loss of proteostasis
• Cellular senescence

🧬 6. Cellular Senescence

• Permanent cell-cycle arrest
• Senescence-associated β-galactosidase
• SASP
• p53-p21 pathway
• p16-Rb pathway
• DNA damage response

🌿 7. Plant Senescence

• Leaf senescence
• Chlorophyll degradation
• Nutrient remobilization
• Hormonal regulation
• Ethylene
• Abscisic acid
• Cytokinin
• Autophagy
• Senescence-associated genes

🌱 8. Programmed Cell Death in Plants

• Developmental cell death
• Xylem differentiation
• Leaf senescence
• Hypersensitive response
• Vacuolar cell death
• Defense-related cell death

🎯 CSIR-NET High-Yield:

Intrinsic apoptosis → Mitochondria → Cytochrome c → Apoptosome → Caspase-9 → Executioner caspases

Extrinsic apoptosis → Death receptor → Caspase-8 → Executioner caspases

Cellular senescence → Permanent cell-cycle arrest → p53/p21 and p16/Rb pathways

📚 CSIR-NET Unit 5 – Quick Revision Map

A → Basic Concepts of Development

B → Gametogenesis & Early Development

C → Animal Morphogenesis & Organogenesis

D → Plant Morphogenesis & Organogenesis

E → PCD, Aging & Senescence

🎯 Most Important CSIR-NET Topics

• Potency, specification, determination and differentiation
• Induction and competence
• Morphogen gradients and positional information
• Stem cells and genomic equivalence
• Cytoplasmic determinants
• Genomic imprinting
• Mutants and transgenic organisms
• Spermatogenesis and oogenesis
• Sperm-egg recognition and fertilization
• Cleavage and blastula formation
• Gastrulation and germ-layer formation
• Plant gametophyte development
• Double fertilization
• Plant embryogenesis and seed development
• Drosophila axis formation
• Maternal-effect genes
• Gap, pair-rule and segment-polarity genes
• Hox genes
• Spemann organizer
• Chick gastrulation
• Vulva development in C. elegans
• Lens induction
• Limb development and regeneration
• Neuronal differentiation
• Metamorphosis
• Sex determination
• Shoot and root apical meristems
• Auxin and plant developmental patterning
• Phyllotaxy
• Photoperiodism and flowering
• Floral meristem development
• ABC model of flower development
• Apoptosis and caspase pathways
• Intrinsic and extrinsic apoptosis
• Autophagy
• Cellular senescence
• Plant senescence

📖 Recommended Study Sequence:

🧬 Basic Developmental Concepts → 🥚 Gametogenesis & Fertilization → 🌀 Gastrulation → 🐣 Animal Development → 🌱 Plant Development → ☠️ Programmed Cell Death → ⏳ Aging & Senescence