figure 20.1 sperm and egg differ greatly in size
TRANSCRIPT
Figure 20.1 Sperm and Egg Differ Greatly in Size
Figure 20.4 Patterns of Cleavage in Four Model Organisms (Part 1)
Figure 20.4 Patterns of Cleavage in Four Model Organisms (Part 2)
Figure 20.5 The Mammalian Zygote Becomes a Blastocyst (Part 2)
Figure 20.7 Twinning in Humans
Two BlastulasTwo Blastulas
zygote
blastula
gastrulaendoderm
glands
pancreas, liver
lining ofrespiratory tract
lining ofdigestive tract
pharynx
mesoderm circulatorysystem
blood, vessels
somites
ectoderm
gonads
kidney
ventralnerve cord
neural crest
chordates vertebrates
integuments
lining ofthoracic and
abdominal cavities
outer covering of internal organs
dermissegmented
muscles
brain,spinal cord,
spinal nerves
gill arches,sensory ganglia,
Schwann cells,adrenal medulla
notochord
heart
skeleton
The Primary The Primary Germ LayersGerm Layers
epidermis
Figure 20.8 Gastrulation in Sea Urchins
Figure 20.9 Gastrulation in the Frog Embryo (Part 1)
Figure 20.9 Gastrulation in the Frog Embryo (Part 2)
Figure 20.9 Gastrulation in the Frog Embryo (Part 3)
NeurulationNeurulation“For the real amazement, if you wish to be amazed, is this process. You start out as a single cell derived from the coupling of a sperm and an egg; this divides in two, then four, then eight, and so on, and at a certain stage there emerges a single cell which has as all its progeny the human brain. The mere existence of such a cell should be one of the great astonishments of the earth. People ought to be walking around all day, all through their waking hours calling to each other in endless wonderment, talking of nothing except that cell.”
--Lewis Thomas
Figure 20.15 Neurulation in the Frog Embryo (Part 1)
Figure 20.15 Neurulation in the Frog Embryo (Part 2)
Figure 20.16 The Development of Body Segmentation
Figure 20.10 Spemann’s Experiment
Figure 20.11 The Dorsal Lip Induces Embryonic Organization
Figure 20.2 The Gray Crescent
Figure 20.3 Cytoplasmic Factors Set Up Signaling Cascades
Figure 20.12 Molecular Mechanisms of the Primary Embryonic Organizer
NC
Shh
sclerotome
dermomyotomemotorneurons
fp
dorsal epidermal ectoderm
NTWnt?
somite
Wnt
BMP-4FGF5?
lateral mesoderm
NT-3
multiple signals pattern the vertebrate neural tube and somite
Figure 19.9 Embryonic Inducers in the Vertebrate Eye
Induction in eye development
Figure 19.10 Induction during Vulval Development in C. elegans (Part 1)
Figure 19.10 Induction during Vulval Development in C. elegans (Part 2)
Origami:sets of instructions
(programs)to build 3-D models of organisms out of
paper –Is this how
developmental programs work?
DifferentiatedCell Types
B C D E F G HA
Differentiation
Determination
The “landscape” of developmental programs:The determination of different cell types involvesprogressive restrictions in their developmental potentials. When a cell “chooses” a particular fate, it is said to be determined. Differentiation follows determination, as the cell elaborates a cell-specific developmental program.
40Mouse Liver ProteinsMouse Liver Proteins Mouse Lung ProteinsMouse Lung Proteins
2-D Electrophoresis of proteins extracted from two 2-D Electrophoresis of proteins extracted from two different mouse tissuesdifferent mouse tissues
AA BB
Cell types A & B share a common set of “housekeeping” gene products and a set of
unique “luxury” gene products that represent the A or B developmental program
Cell types A & B share a common set of “housekeeping” gene products and a set of
unique “luxury” gene products that represent the A or B developmental program
A & BA & B
Sets of gene productsin two cell types
Figure 19.2 Developmental Potential in Early Frog Embryos
Figure 19.3 Cloning a Plant (Part 1)
Figure 19.3 Cloning a Plant (Part 2)
Figure 19.4 A Clone and Her Offspring (Part 1)
Figure 19.4 A Clone and Her Offspring (Part 2)
Figure 19.4 A Clone and Her Offspring (Part 3)
Figure 19.5 Cloned Mice
21_41_cloning.jpg
What is a stem cell?
differentiated cell
determined cell
stem cell
21_39_hemopoietic.jpg
Recent breakthroughs in stem cell research :
- stem cells can be obtained from adults and embryos/fetal tissue
- stem cells are multipotent!
-this very likely has theraputic value
DifferentiatedCell Types
B C D E F G HA
Differentiation
Determination
The “landscape” of developmental programs:The determination of different cell types involvesprogressive restrictions in cellular developmental potentials. When a cell “chooses” a particular fate, it is said to be determined. Differentiation follows determination, as the cell elaborates a cell-specific developmental program.
Uses of human embryos
• obtain stem cells
• somatic cell transfer, then obtain stem cells
• use stem cells that are coaxed to develop into different tissues for therapeutic purposes
Figure 20.14 A Human Blastocyst at Implantation
Week 1
Week 2
Week 4
Week 3
Week 5
Figure 19.6 The Potential Use of Embryonic Stem Cells in Medicine (Part 1)
Figure 19.6 The Potential Use of Embryonic Stem Cells in Medicine (Part 2)
Figure 19.7 Asymmetry in the Early Embryo (Part 1)
Figure 19.7 Asymmetry in the Early Embryo (Part 2)
Figure 19.8 The Principle of Cytoplasmic Segregation
Figure 19.9 Embryonic Inducers in the Vertebrate Eye
Figure 19.11 Apoptosis Removes the Tissue between Fingers
Figure 19.12 Organ Identity Genes in Arabidopsis Flowers (Part 1)
Figure 19.12 Organ Identity Genes in Arabidopsis Flowers (Part 2)
Figure 19.13 A Nonflowering Mutant
c.
b.
Nursecells
AnteriorPosterior
Movement ofmaternal mRNA
Oocyte
Folliclecells
Fertilized egg
a.
d.
e.
Three larval stages
Syncytial blastoderm
Cellular blastoderm
Nuclei line up alongsurface, and membranesgrow between them toform a cellular blastoderm.
Segmented embryo prior to hatching
Metamorphosis
Abdomen
Thorax
Head
Hatching larva
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Nucleus
Embryo
Egg with maternally-depositedmRNA
A P
bicoid nanos
Gradients of informational proteinsencoded by maternal mRNA
Gap Genes
KnirpsKrupplehunchback
Pair RuleGenes
Segment PolarityGenes Homeotic
Genes
Figure 19.15 A Gene Cascade Controls Pattern Formation in the Drosophila Embryo
Fig. 19.13
Figure 19.14 Bicoid and Nanos Protein Gradients Provide Positional Information (Part 1)
Figure 19.14 Bicoid and Nanos Protein Gradients Provide Positional Information (Part 2)
hunchback & Krupple - gap class
even skipped - pair rule class
fushi tarazu (ftz) & even skipped (eve) - pair rule class
engrailed - segment polarity class
Fig. 19.17
40wild-type Antennapedia
mutant
Fly heads
Fig. 19.18
40Hoxb-4 knockoutwildtype
mouse
40