CB&DG Lecture 2
Mechanism of developmental processes
Morphogenesis during embryogenesis
C.elegan morphogenesis
Stained cell membrane and nuclei with different dyes
Micrograph
Used by developmental geneticists
Main question in developmental genetics: how fertilised eggs generate a complex organism
A programme of differential gene expression leads to different cell types in a multicellular organism- lecture 1
Cell types organised successively into tissues, organs, organ systems and whole organism.
A genetic programme regulates embryonic development
The development from zygote (diploid cell resulting from the fusion of 2 haploid gametes)to adult results from 3
major processes:
1. Cell division
2. Cell differentiation
3. Morphogenesis
Ontogenesis = from embryo to mature adult
Some animals have many larva stages in between
3 major processes are required throughout development
Embryonic development starts with a single cell- fertilised egg
Mitotic division
- Provides cellular material for formation of organs and tissues
Cell differentiation
- Process by which cells become specialised in structure and function because express specific genes
Morphogenesis
- Physical processes that result in the typical shape of tissues, organs and whole organism
- Morphogenesis is a consequence of the generation of different cell fates (end goal).
At the cellular level, which mechanisms are involved in generation of different cell fates?
1. Cytoplasmic determinants
2. Induction – short range from one cell to the next
3. Induction- long range by morphogens
4. Lateral inhibition
1. Cytoplasmic determinants
, CB&DG Lecture 2
An egg’s cytoplasm contains RNA, Proteins, other substances distributed unevenly in the unfertilised egg.
In early development, cytoplasmic determinants are maternal substances in the egg that e.g. regulate the formation of
the axes.
As zygote divides by mitosis, cell contains different cytoplasmic determinants, which lead to different gene expression.
After mitosis the cytoplasmic determinants are evenly distributed
Uneven distribution of cell fate determinants during later stages: example neuronal stem cells
Self-renewal capacity
Asymmetric cell division (= uneven distribution of cell fate determinants)
Pluripotent = can generate different cell types
Neuronal cell fate determinants are localised to the neural precursor
Proteins found in the top section of cell become 1 daughter cell
Proteins in the bottom of the cell become into 2 nd daughter cell
Get different cell fate
Mechanism of developmental processes
Morphogenesis during embryogenesis
C.elegan morphogenesis
Stained cell membrane and nuclei with different dyes
Micrograph
Used by developmental geneticists
Main question in developmental genetics: how fertilised eggs generate a complex organism
A programme of differential gene expression leads to different cell types in a multicellular organism- lecture 1
Cell types organised successively into tissues, organs, organ systems and whole organism.
A genetic programme regulates embryonic development
The development from zygote (diploid cell resulting from the fusion of 2 haploid gametes)to adult results from 3
major processes:
1. Cell division
2. Cell differentiation
3. Morphogenesis
Ontogenesis = from embryo to mature adult
Some animals have many larva stages in between
3 major processes are required throughout development
Embryonic development starts with a single cell- fertilised egg
Mitotic division
- Provides cellular material for formation of organs and tissues
Cell differentiation
- Process by which cells become specialised in structure and function because express specific genes
Morphogenesis
- Physical processes that result in the typical shape of tissues, organs and whole organism
- Morphogenesis is a consequence of the generation of different cell fates (end goal).
At the cellular level, which mechanisms are involved in generation of different cell fates?
1. Cytoplasmic determinants
2. Induction – short range from one cell to the next
3. Induction- long range by morphogens
4. Lateral inhibition
1. Cytoplasmic determinants
, CB&DG Lecture 2
An egg’s cytoplasm contains RNA, Proteins, other substances distributed unevenly in the unfertilised egg.
In early development, cytoplasmic determinants are maternal substances in the egg that e.g. regulate the formation of
the axes.
As zygote divides by mitosis, cell contains different cytoplasmic determinants, which lead to different gene expression.
After mitosis the cytoplasmic determinants are evenly distributed
Uneven distribution of cell fate determinants during later stages: example neuronal stem cells
Self-renewal capacity
Asymmetric cell division (= uneven distribution of cell fate determinants)
Pluripotent = can generate different cell types
Neuronal cell fate determinants are localised to the neural precursor
Proteins found in the top section of cell become 1 daughter cell
Proteins in the bottom of the cell become into 2 nd daughter cell
Get different cell fate
