Genetic Basis of Embryonic Development

What a Difference a _______Makes!

What a Difference a Week Makes!

I. Embryonic Development Involves 3 interrelated processes: 1 I. Embryonic Development Involves 3 interrelated processes: 1. Cell ________: cells increase in number

I. Embryonic Development (Fig. 21 I. Embryonic Development (Fig. 21.3) Involves 3 interrelated processes: 1. Cell division : cells increase in number

I. Embryonic Development (Fig. 21 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 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 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 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 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 II. Plant vs. Animal Development 1. Animal development involves ________ of cells/tissues necessary to transform the embryo.

II. Plant vs. Animal Development 1 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 2. Plant development involves continual growth throughout lifetime (embryonic regions of shoot tips and _____).

2. Plant development involves continual 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 albumin (_______ protein) Lens cells _________ proteins

Example of Differential Gene Expression: Liver Cells & Lens Cells – same DNA Liver cells albumin (blood protein) Lens cells 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.

At the two cell stage: Are the cells genetically identical? 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

At the two cell stage: Are the cells genetically identical? 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.

At the two cell stage: Are the cells genetically identical? 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.

At the two cell stage: Are the cells genetically identical? 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____ _____________

At the two cell stage: Are the cells genetically identical? 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 IV. Morphogenesis (Shape & Body Pattern) A. ____-______ _________: Mom tells Junior which way is “up” – bicoid gene in Drosophila

IV. Morphogenesis (Shape & Body Pattern) A 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 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 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 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 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 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 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 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 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

Activation of Destructive Enzymes 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 (Colored Bands)