Download Developmental Gene Expression Part I

Warm-Up (1/6)
On the piece of white paper from the back, answer
the following question.
Explain how a mutation affects
gene expression.
Name
Date
Period
2E.1b: Induction of transcription factors during development results in
sequential gene expression.
2E.1b.3: Temperature and the availability of water determine seed
germination in most plants.
2E.1b.4: Genetic mutations can result in abnormal development.
2E.1b.5: Genetic transplantation experiments support the link between
gene expression and normal development.
2E.1b.6: Genetic regulation by microRNAs plays an important role in the
development of organisms and the control of cellular functions.
3B.2a: Signal transmission within and between cells mediates gene
expression.
Illustrative example: expression of the SRY gene triggers the male sexual
development pathway in animals.
Gene Regulation During Development
transcription factors
fertilized egg
(zygote)
16-cell embryo
2-cell embryo
8-cell embryo
Transcription
factors (TFs)
determine
cell types
~1 million-cell
(6-week-old)
embryo
Gene Regulation During Development
TFs cause
sequential
gene
expression
Gene Regulation During Development
Transplantation experiments show that gene expression
determines cell types
2-day embryo
6-week embryo
Gene Regulation During Development
Transplantation experiments show that gene expression
determines cell types
4-week embryo
6-week embryo
Gene Regulation During Development
Mutations in
transcription factors
cause birth defects.
Neural Tube Closure (NTC) Defects
2E.1b: Induction of transcription factors during development results in
sequential gene expression.
2E.1b.3: Temperature and the availability of water determine seed
germination in most plants.
2E.1b.4: Genetic mutations can result in abnormal development.
2E.1b.5: Genetic transplantation experiments support the link between
gene expression and normal development.
2E.1b.6: Genetic regulation by microRNAs plays an important role in the
development of organisms and the control of cellular functions.
3B.2a: Signal transmission within and between cells mediates gene
expression.
Illustrative example: expression of the SRY gene triggers the male sexual
development pathway in animals.
Environmental Stimuli of Gene Regulation
Water and sunlight
activate transcription
factors in seeds.
Post-Transcriptional Regulation
protein
microRNAs bind to
coding RNA and
prevent translation
microRNA
Dysfunctional doublestranded RNA
RNA
microRNA-coding gene
protein-coding gene
2E.1b: Induction of transcription factors during development results in
sequential gene expression.
2E.1b.3: Temperature and the availability of water determine seed
germination in most plants.
2E.1b.4: Genetic mutations can result in abnormal development.
2E.1b.5: Genetic transplantation experiments support the link between
gene expression and normal development.
2E.1b.6: Genetic regulation by microRNAs plays an important role in the
development of organisms and the control of cellular functions.
3B.2a: Signal transmission within and between cells mediates gene
expression.
Illustrative example: expression of the SRY gene triggers the male sexual
development pathway in animals.
Post-Transcriptional Regulation
Cell membrane
Nucleus
SRY
P 2nd
messenger
ligand
receptor
SRY transcription factor
activates expression of
transcription factors for male
sexuality genes.
Post-Transcriptional Regulation
SRY
SRY
future
sperm
Other TFs activated
SRY
future
egg
SRY transcription factor
activates expression of
transcription factors for male
sexuality genes.
Default egg TFs
expressed
Critical Thinking Question #1
Discuss this question with your partner and write or
represent it. I will call on three people to share their
partners’ answers.
SRY is a gene which encodes a transcription factor
responsible for activating expression of other
transcription factors responsible for the
development of male sexuality in animals. Predict
the effects of low levels of SRY protein on the
expression of these transcription factors and the
resulting phenotype in the developing animal.
Critical Thinking Question #2
Discuss this question with your partner and write or
represent it. I will call on three people to share their
partners’ answers.
A chimpanzee’s DNA is 96% identical to a human
being’s DNA. Most of this similarity, however, is in
protein-coding DNA: the genes themselves.
Describe how a chimpanzee zygote with
chimpanzee DNA will give rise to a completely
different animal from a human zygote with human
DNA.
Closure
On the piece of white paper from the
back, answer the following question:
Why is a butterfly dramatically
different phenotypically from a
caterpillar, even though it has
exactly the same DNA?
Name
Date
Period
Scale
1 – 10