Download Embryonic Development

Genetic Basis of Embryonic
Development
What a Difference a _______Makes!
What a Difference a Week Makes!
I. Embryonic Development
Involves 3 interrelated processes:
1. Cell ________: cells increase in
number
I. Embryonic Development (Fig. 21.3)
Involves 3 interrelated processes:
1. Cell division : cells increase in
number
I. Embryonic Development (Fig. 21.3)
Involves 3 interrelated processes:
1. Cell division : cells increase in
number
2. Cell __________: cells become
“specialized” in __________ &
________
I. Embryonic Development (Fig. 21.3)
Involves 3 interrelated processes:
1. Cell division : cells increase in
number
2. Cell differentiation: cells become
“specialized” in ___________ &
___________
I. Embryonic Development (Fig. 21.3)
Involves 3 interrelated processes:
1. Cell division : cells increase in
number
2. Cell differentiation: cells become
“specialized” in structure &
function
I. Embryonic Development (Fig. 21.3)
Involves 3 interrelated processes:
1. Cell division : cells increase in
number
2. Cell differentiation: cells become
“specialized” in structure & function – cells
are not ________ distributed but are
organized into organs & tissues
I. Embryonic Development (Fig. 21.3)
Involves 3 interrelated processes:
1. Cell division : cells increase in
number
2. Cell differentiation: cells become
“specialized” in structure & function – cells
are not randomly distributed but are
organized into organs & tissues
3. _____________: physical process that
gives an organism its shape.
3. Morphogenesis: physical process that
gives an organism its shape.
II. Plant vs. Animal Development
1. Animal development involves
________ of cells/tissues necessary
to transform the embryo.
II. Plant vs. Animal Development
1. Animal development involves
movement of cells/tissues necessary
to transform the embryo.
Example: Blastula to Gastrula stage
When do plants stops growing?
2. Plant development involves _________
growth throughout lifetime (embryonic
regions of shoot tips and _____).
2. Plant development involves continual
growth throughout lifetime (embryonic
regions of shoot tips and _____).
2. Plant development involves continual
growth throughout lifetime (embryonic
regions of shoot tips and roots).
What about animals?
2. Plant development involves continual
growth throughout lifetime (embryonic
regions of shoot tips and roots).
*In animals, growth _____, but cells must
be ________ throughout animal’s lifetime
2. Plant development involves continual
growth throughout lifetime (embryonic
regions of shoot tips and roots).
*In animals, growth stops, but cells must
be _______throughout animal’s lifetime.
2. Plant development involves continual
growth throughout lifetime (embryonic
regions of shoot tips and roots).
*In animals, growth stops, but cells must
be replaced throughout animal’s lifetime.
Examples:
2. Plant development involves continual
growth throughout lifetime (embryonic
regions of shoot tips and roots).
*In animals, growth stops, but cells must
be replaced throughout animal’s lifetime.
Examples: (blood cells, skin cells, cells lining
small intestine)
III. Cell Differentiation & Gene Expression (How is
Gene Expression Related to Cell Differentiation?)
• Different cell types (i.e. _____cells and
_____cells) result from differential (_______)
gene expression in cells with the
same_______.
III. How is Gene Expression related to Cell
Differentiation?
• Different cell types (i.e. nerve cells and blood
cells) result from differential (_____) gene
expression in cells with the same_______.
III. Cell Differentiation & Gene Expression
• Different cell types (i.e. nerve cells and blood
cells) result from differential (unique) gene
expression in cells with the same____.
III. Cell Differentiation & Gene Expression
• Different cell types (i.e. nerve cells and blood
cells) result from differential (unique) gene
expression in cells with the same DNA.
*Three major mechanisms of differential gene
expression:
1. Regulation of _______ synthesis.
III. Cell Differentiation & Gene Expression
• Different cell types (i.e. nerve cells and blood
cells) result from differential (unique) gene
expression in cells with the same DNA.
*Three major mechanisms of differential gene
expression:
1. Regulation of protein synthesis.
1. Regulation of protein synthesis:
• ____________: Promotor Region controls
(AKA: gene __________), mRNA processing
(_________), micro RNAs (_______) and small
interfering RNAs (________) both interfere
with mRNA transcript therefore affect
____________.
1. Regulation of protein synthesis:
• Transcription: Promotor Region controls (AKA:
gene __________), mRNA processing
(_________), micro RNAs (_______) and small
interfering RNAs (________) both interfere
with mRNA transcript therefore affect
____________.
1. Regulation of protein synthesis:
• Transcription: Promotor Region controls (AKA:
gene switches), mRNA processing
(_________), micro RNAs (_______) and small
interfering RNAs (________) both interfere
with mRNA transcript therefore affect
____________.
1. Regulation of protein synthesis:
• Transcription: Promotor Region controls,
mRNA processing (introns), micro RNAs
(miRNAs) and small interfering RNAs (siRNAs)
both interfere with mRNA transcript therefore
affect ______________.
1. Regulation of protein synthesis:
Transcription: Promotor Region controls, mRNA
processing (introns), micro RNAs (miRNAs) and
small interfering RNAs (siRNAs) both interfere
with mRNA transcript therefore affect
translation.
Example of Differential Gene Expression:
Liver Cells & Lens Cells – same DNA
Liver cells
Lens cells
albumin (_______ protein)
_________ proteins
Example of Differential Gene Expression:
Liver Cells & Lens Cells – same DNA
Liver cells
Lens cells
albumin (blood protein)
crystallin proteins
What is the
same between
these cells?
What is different?
Both cells have
the same DNA
& are affected
by activators!
Available
Activators vary
between the
cells.
• How do cells “know” which genes should be
expressed at a certain time during embryonic
development?
• At the two cell stage: Are the cells genetically
identical?
2. ____________ _____________– located in the
_______ (______, __________, ____________) are
unevenly distributed
• How do cells “know” which genes should be
expressed at a certain time during embryonic
development?
• At the two cell stage: Are the cells genetically
identical?
2. Maternal Substances – located in the ____
(______, __________, ____________) are unevenly
distributed.
• How do cells “know” which genes should be
expressed at a certain time during embryonic
development?
• At the two cell stage: Are the cells genetically
identical?
2. Maternal Substances – located in the egg
(______, __________, ____________) are unevenly
distributed.
• How do cells “know” which genes should be
expressed at a certain time during embryonic
development?
• At the two cell stage: Are the cells genetically
identical?
2. Maternal Substances – located in the egg (mRNA,
proteins, organelles) are unevenly distributed
*Subsequent cells (after fertilization) will receive unequal
amounts of these – this leads to____ _____________
• How do cells “know” which genes should be
expressed at a certain time during embryonic
development?
• At the two cell stage: Are the cells genetically
identical?
2. Maternal Substances – located in the egg (mRNA,
proteins, organelles) are unevenly distributed
*Subsequent cells (after fertilization) will receive unequal
amounts of these – this leads to cell differentiation
Differential Gene
Expression
3. _________ __________– One embryonic cell can
cause changes in nearby embryonic cells through
molecular signals – this is called ___________.
3. Cell-to-cell Communication – One embryonic cell can
cause changes in nearby embryonic cells through
molecular signals – this is called ___________.
3. Cell-to-cell Communication – One embryonic cell can
cause changes in nearby embryonic cells through
molecular signals – this is called induction.
3. Cell-to-cell Communication – One embryonic cell can
cause changes in nearby embryonic cells through
molecular signals – this is called induction.
*Signals can either be sent through the ________ of one
embryonic cell anchoring with ________ sites of another cell or
secretory _______ binding to glycoproteins of the receiving cell.
3. Cell-to-cell Communication – One embryonic cell can
cause changes in nearby embryonic cells through
molecular signals – this is called induction.
*Signals can either be sent through the glycoproteins of one
embryonic cell anchoring with ________ sites of another cell or
secretory _______ binding to glycoproteins of the receiving cell.
3. Cell-to-cell Communication – One embryonic cell can
cause changes in nearby embryonic cells through
molecular signals – this is called induction.
*Signals can either be sent through the glycoproteins of one
embryonic cell anchoring with receptor sites of another cell or
secretory _______ binding to glycoproteins of the receiving cell.
Fig. 21.16
3. Cell-to-cell Communication – One embryonic cell can
cause changes in nearby embryonic cells through
molecular signals – this is called induction.
*Signals can either be sent through the glycoproteins of one
embryonic cell anchoring with receptor sites of another cell or
secretory protein binding to glycoproteins of the receiving cell.
Fig. 21.15
**Overall: A signal molecule sends a cell down
a specific ______________ ______by causing a
______ in its gene ____________that results in
observable cellular ____________.
**Overall: A signal molecule sends a cell down
a specific developmental path by causing a
change in its gene ____________that results in
observable cellular ____________.
**Overall: A signal molecule sends a cell down
a specific developmental path by causing a
change in its gene expression that results in
observable cellular changes.
Fig. 21.16
Fig. 21.15
C. Elegans
How many cell
divisions lead
to mature
intestinal cells
in C. Elegans?
IV. Morphogenesis (Shape & Body Pattern)
A. ____-______ _________: Mom tells Junior
which way is “up” – bicoid gene in Drosophila
IV. Morphogenesis (Shape & Body Pattern)
A. Egg-polarity Genes: Mom tells Junior which
way is “up” – bicoid gene in Drosophila
What stage
of fruit fly
development
is this?
IV. Morphogenesis (Shape & Body Pattern)
A. Egg-polarity Genes: Mom tells Junior which
way is “up” – bicoid gene in Drosophila
**What leads to egg polarity?
IV. Morphogenesis (Shape & Body Pattern)
A. Egg-polarity Genes: Mom tells Junior which
way is “up” – bicoid gene in Drosophila
**What leads to egg polarity?
Nurse cells produce bicoid protein at the anterior end
of the cell. (Maternal substances are unevenly
distributed in the egg from the get go)
IV. Morphogenesis (Shape & Body Pattern)
A. Egg-polarity Genes: Mom tells Junior which
way is “up” – bicoid gene in Drosophila
B. ______________ _______: Control
where/how many body __________ will form
IV. Morphogenesis (Shape & Body Pattern)
A. Egg-polarity Genes: Mom tells Junior which
way is “up” – bicoid gene in Drosophila
B. Segmentation Genes: Control where/how
many body ___________will form
IV. Morphogenesis (Shape & Body Pattern)
A. Egg-polarity Genes: Mom tells Junior which
way is “up” – bicoid gene in Drosophila
B. Segmentation Genes: Control where/how
many body segments will form
IV. Morphogenesis (Shape & Body Pattern)
A. Egg-polarity Genes: Mom tells Junior which way is
“up” – bicoid gene in Drosophila
B. Segmentation Genes
Control where/how many body segments will form
C. ___________ ________ specify the types of
appendages /structures that each segment will form.
IV. Morphogenesis (Shape & Body Pattern)
A. Egg-polarity Genes: Mom tells Junior which way is “up” – bicoid
gene in Drosophila
B. Segmentation Genes
Control where/how many segments will form
C. Homeotic Genes specify the types of appendages /structures
that each segment will form.
**Species that have a ________ common ancestor tend to have
homeotic genes with similar base pair sequences.
IV. Morphogenesis (Shape & Body Pattern)
A. Egg-polarity Genes: Mom tells Junior which way is “up” – bicoid
gene in Drosophila
B. Segmentation Genes
Control where/how many segments will form
C. Homeotic Genes specify the types of appendages /structures
that each segment will form.
**Species that have a close common ancestor tend to have
homeotic genes with similar base pair sequences.
• Mutations in homeotic genes can
have dramatic physical effects
on the organism!
• These mutations lead to major
__________changes in a short
period of time for a species.
• Mutations in homeotic genes can
have dramatic physical effects
on the organism!
• These mutations lead to major
phenotypic changes in a short
period of time for a species.
D. Apoptosis (Cell Suicide)
•
Programmed ____death
D. Apoptosis (Cell Suicide)
•
Programmed cell death
•
Triggered by ______molecules that
activate a cascade of _______ proteins in the
cells that are destined to die.
D. Apoptosis (Cell Suicide)
•
Programmed cell death
•
Triggered by signal molecules that activate
a cascade of ________proteins in the cells
that are destined to die.
D. Apoptosis (Cell Suicide)
•
Programmed cell death
•
Triggered by signal molecules that activate
a cascade of suicide proteins in the cells that
are destined to die.
D. Apoptosis (Cell Suicide)
•
Programmed cell death
•
Triggered by signal molecules that activate
a cascade of suicide proteins in the cells that
are destined to die.
• Cell death may be necessary for body
formation
Effect of apoptosis during paw
development in a mouse
Apoptosis of a white blood cell (forms
lobes & shrinks – lobes are eventually
shed as membrane-bound cell fragments
The role of
Ced-9 protein
is to
___________
Ced-4 activity
The role of
Ced-9 protein
is to inhibit
Ced-4 activity
Death Signal
CED-9 deactivation
CED-3 & 4
Activation
Activation of
Destructive
Enzymes
6. Compare/Contrast homeotic
genes for a mouse and a fruit fly
Homeotic Genes
(Colored Bands)