Course Outline

1
Lecture 1

• Course Outline
• Central problem in Development
• Terms
• Cellular mechanisms of determination

2
Objectives

• Lectures application of genetic analysis to
  problems in development. Emphasis on problem
  solving as opposed to rote memorization.
• Labs Illustration of some basic techniques used
  in Developmental genetics. Lab report written in
  the format of a scientific paper.

3
Schedule of Lectures
Jan 12 Lecture 1 Introduction to developmental
genetics Jan 19 Lecture 2 Introduction to
genetic dissection screens, complementation and
epistasis. Jan 26 Lecture 3 Drosophila cell
biology Feb 2 Lecture 4 Modern Drosophila
genetics Feb 9 Lecture 5 Anterior posterior
axis formation Feb 16 Lecture 6 Anterior
posterior axis formation continued Feb 23 SLACK
WEEK March 1 Lecture 7 Morphogens March 8
Lecture 8 Nuclear gradients and the habits of
developmental signaling pathways March 15
Lecture 9 Short course on C. elegans cell
biology and genetic analysis. March 22 Lecture
10 Lateral inhibitionemergent properties in
development March 29 Lecture 11 Short course on
Evolution and Development. April 5 Lecture 12
Experimental approaches to Evo Devo. Paper due.
4
Date for the Midterm examination
Monday February 27, 2012 This is the Monday
right after slack week 7-10PM.
This midterm will cover material up to Lecture 6
Anterior Posterior axis.
5
The course web site can be found at
instruct.uwo.ca/biology/4540g
This web site contains all the information you
need for this course. Consult it. Explore it.
6
Schedule of the Labs and in class tests
Jan 9/10 NO LAB Jan 16/17 Lab 1 Preparation of
first instar larval cuticles (test) Jan 23/24
Lab 2 Ectopic expression of Fushi tarazu (come in
the day before). Fixation of embryos for Labs 34
(test) Jan 30/31 Lab 3 Engrailed antibody
staining (long lab) (test) Feb 6/7 Lab 4
Wingless in situ hybridization (come in the day
before long lab) (test) Feb 13/14 Lab 5
Beta-galactosidase staining for assaying ftz
enhancer activity. (test) NO MORE LABS
7
Long labs
Jan 9/10 NO LAB Jan 16/17 Lab 1 Preparation of
first instar larval cuticles Jan 23/24 Lab 2
Ectopic expression of Fushi tarazu (come in the
day before). Fixation of embryos for Labs
34 Jan 30/31 Lab 3 Engrailed antibody staining
(long lab) Feb 6/7 Lab 4 Wingless in situ
hybridization (come in the day before long
lab) Feb 13/14 Lab 5 Beta-galactosidase staining
for assaying ftz enhancer activity. NO MORE LABS
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
The lab test on the readings
Why am I doing this to you? In the past I
expected students to read the papers on their own
before coming to the lab. Over the years it
become clear that this was not occurring.
Reading in the first half of the term saves a lot
of pain later. Since I know this, I am being a
pain now.
12
Format of the test on the readings
You will have 5 minutes to answer one question at
the beginning of the lab. The question asked
will be different on Monday and Tuesday.
13
This and the next lecture will focus on
definition of the terms and basic genetic
concepts used in Developmental genetics.
14
The central problem in Development
How is the information stored in linear
DNA transformed over time into a three
dimensional multicellular organism?
15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
From this perspective the problem seems limitless.
However, the size of the genome provides a limit
on the problem because all information required
for hand development is somehow encoded in the
genome.
19
(No Transcript)
20
(No Transcript)
21
What is animal development?
22
What is animal development?

• It is an essential part of our and all animal
  life cycles.

23
What is animal development?

• It is an essential part of our and all animal
  life cycles.
• At the present time only life can beget life.

24
General animal life cycle
Soma
Germ-line
fertilization
fertilization
25
General animal life cycle
Soma
Somatic germ-line division
Germ-line
fertilization
fertilization
26
General animal life cycle
Soma
Somatic germ-line division
Germ-line
fertilization
fertilization
Life does not begin at fertilization it is a
continuous process.
27
What are the characteristics of animal
development?
28
Development at its most basic level.
Single celled Zygote
Decisions
Complex multicellular organism of many
specialized cell types and organs.
29
Two terms used in Developmental Biology.
Determination
Differentiation
30
More terms

• Cell specification
• versus
• Pattern formation

31
Examples of cell specification
Lens each cell as it differentiates
becomes transparent.
Red blood cell no nucleus packed with hemoglobin.
32
(No Transcript)
33
Example of pattern formation
You distinguish an arm from a leg by its shape
and not by what it is made up of which is
basically the same stuff bone, muscle, nerves
etc..
This is an abstract ability, because shape is a
quality defined only by what it is.
34
Cellular mechanisms of determination

• Intrinsic
• Extrinsic

35
Example of an intrinsic mechanism Assymetric
determinant
Bicoid mRNA and protein are assymetrically
localized in the cell.
mRNA
protein
Posterior
Anterior
36
Extrinsic mechanisms

• A) Lateral inhibition
• B) Induction

37
Lateral inhibition during neurogenesis in
Drosophila.
Example of an emergent property because before
the process starts you can not tell which cell
will be neurogenic and which will be epithelial.
38
Delta ligand
Notch receptor
Start off with identical levels of expression
in two cells.
39
Delta ligand
Notch receptor
No Net signal
Start off with identical levels of expression
in two cells.
40
Due to a stochastic (random, chance) event one
cell expresses more Delta ligand than the other.
Dl
The net signal is in this direction. The
activation of Notch receptor results in decreased
Delta expression.
41
Neuroblast
Epithelial
Epithelial
Notch
Neuroblast
When Notch or Delta are absent, the ectoderm
cells become neurogenic. The cell that becomes
the neuroblast inhibits the surrounding cells
from this fate, and telling them to become
epithelial cells instead. Lateral inhibition.
42
Induction
A cell or group of cells removed from a second
cell
1
2
that directs the developmental fate of a second
cell or group of cells.
43
Example of induction
Anchor cell-gonad
signals
Epidermis
Vulva
44
What molecules control determination?
45
(No Transcript)
46
Analysis of gene regulation cis regulation.
ORF
gene something
Brain
Gut
embryo of something
47
Translational fusion to a reporter gene
ATG
Reporter gene
48
Regulatory regions of the gene
GFP
ATG
TATA
49
Regulatory regions of the gene
GFP
ATG
TATA
Brain
Gut
50
Regulatory regions of the gene
GFP
ATG
TATA
Brain
Brain
Gut
Gut
51
Mutagenesis
Brain
Gut
52
Mutagenesis
Brain
Gut
Brain
Gut
53
Mutagenesis
Brain
Gut
Brain
Gut
54
Mutagenesis
Brain
Gut
Brain
Gut
Brain
Gut
55
Mutagenesis
Brain
Gut
Brain
Gut
Brain
Gut
56
Mutagenesis
Brain
Gut
Brain
Gut
Brain
Gut
Brain
Gut
57
Mutagenesis
Brain
Gut
Brain
Gut
Brain
Gut
Brain
Gut
58
Mutagenesis
Brain
Gut
Gut enhancer
Brain
Gut
Brain enhancer
Brain
Gut
Gut silencer
Brain
Gut
59
Transcriptional fusion
Gut silencer
Gut enhancer
GFP
ATG
Brain enhancer
Heterologous TATA box
Brain
Gut
60
GFP
ATG
Brain
Gut
61
GFP
ATG
Brain
Gut
Gut enhancer
ATG
Brain
Gut
Brain enhancer
ATG
Brain
Gut
62
GFP
ATG
Brain
Gut
Gut enhancer
ATG
Brain
Gut
Brain enhancer
ATG
Brain
Gut
63
GFP
ATG
Brain
Gut
Gut enhancer
ATG
Brain
Gut
Brain enhancer
ATG
Brain
Gut
Gut enhancer
ATG
Brain
Gut
Gut silencer
64
GFP
ATG
Brain
Gut
Gut enhancer
ATG
Brain
Gut
Brain enhancer
ATG
Brain
Gut
Gut enhancer
ATG
Brain
Gut
Gut silencer
65
Important property Necessary and Sufficient
66
Developmental pathways
67
Transcription factor signal transcription factor
pathways