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 Blastulas

zygote blastula gastrula endoderm glands pancreas, liver lining of respiratory tract lining of digestive tract pharynx mesoderm circulatory system blood, vessels somites ectoderm gonads kidney ventral nerve cord neural crest chordatesvertebrates integuments lining of thoracic and abdominal cavities outer covering of internal organs dermis segmented muscles brain, spinal cord, spinal nerves gill arches, sensory ganglia, Schwann cells, adrenal medulla notochord heart skeleton The Primary Germ 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)

Neurulation “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 Neurulation in the Frog Embryo (Part 1)

Figure Neurulation in the Frog Embryo (Part 2)

Figure The Development of Body Segmentation

Figure Spemann’s Experiment

Figure The Dorsal Lip Induces Embryonic Organization

Figure 20.2 The Gray Crescent

Figure 20.3 Cytoplasmic Factors Set Up Signaling Cascades

Figure Molecular Mechanisms of the Primary Embryonic Organizer

NC Shh sclerotome dermomyotome motorneurons fp dorsal epidermal ectoderm NT Wnt? somite Wnt BMP-4 FGF5? 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 Induction during Vulval Development in C. elegans (Part 1)

Figure 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?

Differentiated Cell Types BCDEFGHA Differentiation Determination The “landscape” of developmental programs: The determination of different cell types involves progressive 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.

40 Mouse Liver Proteins Mouse Lung Proteins 2-D Electrophoresis of proteins extracted from two different mouse tissues

AB 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 & B Sets of gene products in 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

Differentiated Cell Types BCDEFGHA Differentiation Determination The “landscape” of developmental programs: The determination of different cell types involves progressive 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 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 Apoptosis Removes the Tissue between Fingers

Figure Organ Identity Genes in Arabidopsis Flowers (Part 1)

Figure Organ Identity Genes in Arabidopsis Flowers (Part 2)

Figure A Nonflowering Mutant

c. b. Nurse cells AnteriorPosterior Movement of maternal mRNA Oocyte Follicle cells Fertilized egg a. d. e. Three larval stages Syncytial blastoderm Cellular blastoderm Nuclei line up along surface, and membranes grow between them to form 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-deposited mRNA AP bicoidnanos Gradients of informational proteins encoded by maternal mRNA Gap Genes Knirps Krupplehunchback Pair RuleGenes Segment Polarity Genes Homeotic Genes

Figure A Gene Cascade Controls Pattern Formation in the Drosophila Embryo

Fig

Figure Bicoid and Nanos Protein Gradients Provide Positional Information (Part 1)

Figure 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

40 wild-typeAntennapedia mutant Fly heads

Fig

40 Hoxb-4 knockoutwildtype mouse

40