developmental biology eighth - gbv · the slow block to polyspermy 189 fusion of genetic material...
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Developmenta lBiology EIGHTH
Scott F. Gilbert
P ART 1 Principles ofdevelopmental biologyChapter 1 Developmental biology: The anatomical tradition 3
Chapter 2 Life cycles and the evolution of developmental patterns 25
Chapter 3 Principles of experimental embryology 49
Chapter 4 The genetic core of development 7 7Chapter 5 The paradigm of differential gene expression 10 1Chapter 6 Cell-cell communication in development 139
P ART 2 Early embryonic developmentChapter 7 Fertilization: Beginning a new organism 17 5Chapter 8 Early development in selected invertebrates 21 1
Chapter 9 The genetics of axis specification in Drosophila 253
Chapter 10 Early development and axis formation in amphibians 29 1
Chapter 11 The early development of vertebrates: Fish, birds, and mammals 325
P ART 3 Later embryonic developmen tChapter 12 The emergence of the ectoderm : Central nervous system and epidermis 373
Chapter 13 Neural crest cells and axonal specificity 407
Chapter 14 Paraxial and intermediate mesoderm 443
Chapter 15 Lateral plate mesoderm and endoderm 47 1
Chapter 16 Development of the tetrapod limb 505
Chapter 17 Sex determination 529
Chapter 18 Postembryonic development: Metamorphosis, regeneration, and aging 555
Chapter 19 The saga of the germ line 593
PART 4 Ramifications ofdevelopmental biology
Chapter 20 An overview of plant development 627
Chapter21 Medical implications of developmental biology 655
Chapter 22 Environmental regulation of animal development 693
Chapter 23 Developmental mechanisms of evolutionary change 721
Principles ofPART
Developmental Biology
-
CHAPTER 1 Developmental Biology:The Anatomical Tradition 3
The Questions of Developmental Biology 4
Evolutionary Embryology 1 5
Approaches to Developmental Biology 5
Embryonic homologies 1 6
The Anatomical Approach 5
Medical Embryology and Teratology 1 7
Comparative embryology 5
Genetic malformations and syndromes 1 8
Epigenesis and preformation 6
Disruptions and teratogens 1 8
Naming the parts : The primary germ layers and early
Mathematical Modeling of Development 1 9organs 8
The mathematics of organismal growth 19The four principles of Karl Ernst von Baer 8
The mathematics of patterning 2 1Fate mapping the embryo 10
Coda 23The Cellular Basis of Morphogenesis 1 3
Cell migration 1 3
CHAPTER 2 Life Cycles and the Evolution of Developmental Patterns 2 5
The Circle of Life : The Stages of Animal
n SIDELIGHTS G SPECULATIONS: Rules of Evidence I 3 9Development 25
Development in Flowering Plants 40The frog life cycle 26
Developmental Patterns among the Metazoa 4 2Multicellularity: The Evolution of Differentiation and
The Diploblasts, Protostomes, and Deuterostomes 4 4Morphogenesis 31
n SIDELIGHTS G SPECULATIONS : Totipotency among theThe volvocaceans 31
Flatworms 44n SIDELIGHTS & SPECULATIONS: Sex and Individuality in Volvox 33
Differentiation and morphogenesis in Dictyostelium 36
CHAPTER 3 Principles of Experimental Embryology 4 9Environmental Developmental Biology 49
Morphogen gradients revisited 63Environmental sex determination 50
n SIDELIGHTS & SPECULATIONS : Rules of Evidence II : Controls 65Adaptation of embryos and larvae to their
Stem cells and commitment 6 6environments 50
Morphogenesis and Cell Adhesion 67The Developmental Dynamics of Cell Specification 53
Differential cell affinity 6 8Autonomous specification 53
The thermodynamic model of cell interactions 7 0Syncytial specification 56
Cadherins and cell adhesion 7 1Conditional specification 57
Coda 74
CHAPTER 4 The Genetic Core ofDevelopment 77The Embryological Origins of the Gene Theory 77
RNA Localization Techniques 87Nucleus or cytoplasm : Which controls heredity? 77
Detecting specific mRNAs : RT-PCR 8 7The split between embryology and genetics 79
Microarrays 8 9Early attempts at developmental genetics 79
Macroarrays 8 9
Evidence for Genomic Equivalence 80
Locating mRNAs in space and time : In sit uAmphibian cloning : The restriction of nuclear potency 81
hybridization 9 0
Amphibian cloning: The totipotency of somatic cells 82
Determining the Function of Genes durin gCloning mammals 83
Development 9 2
n SIDELIGHTS & SPECULATIONS : Why Clone Mammals? 85
Transgenic cells and organisms 9 2
Differential Gene Expression 86
Determining the function of a message : Antisense RNA 96
Coda 98
CHAPTER 5 The Paradigm of Differential Gene Expression 10 1Differential Gene Transcription 101
n SIDELIGHTS & SPECULATIONS : The Mechanisms of X
Anatomy of the gene : Active and repressed chromatin 101
Chromosome Inactivation 12 3
Anatomy of the gene : Exons and introns 102
Differential RNA Processing 12 5
Anatomy of the gene : Promoters and enhancers 103
Control of early development by nuclear RNA
Transcription factors 108selection 12 5
Creating families of proteins through differential nRN An SIDELIGHTS & SPECULATIONS : Pioneer Transcription Factors 112
splicing 126Transcription factor cascades 113
Splicing enhancers and recognition factors 12 8n SIDELIGHTS & SPECULATIONS: Studying DNA Regulatory n SIDELIGHTS & SPECULATIONS : Differential nRNA Processing an dElements 11 3
Silencers 116
Drosophila Sex Determination 12 9
Control of Gene Expression at the Level o fMethylation Pattern and the Control of
Translation 130Transcription 116
Differential mRNA longevity 13 0DNA methylation and gene activity 116 Selective inhibition of mRNA translation : Stored oocyt e
n SIDELIGHTS & SPECULATIONS : Genomic Imprinting 117 mRNAs 130Chromatin modification induced by DNA
Control of RNA expression by cytoplasmi cmethylation 118
localization 13 5Insulators 119
n SIDELIGHTS 6 SPECULATIONS : miRNA in Transcriptional Gen eTranscriptional regulation of an entire chromosome:
Regulation 135Dosage compensation 119
Posttranslational regulation of gene expression 137
CHAPTER 6 Cell-Cell Communication in Development 13 9
Induction and Competence 139
n SIDELIGHTS CSPECULATIONS : Stem Cell Niches 15 7
Cascades of induction : Reciprocal and sequential
Other paracrine factors 15 8inductive events 141
Cell Death Pathways 15 8Instructive and permissive interactions 142
Juxtacrine Signaling 16 0Epithelial-mesenchymal interactions 143
The Notch pathway : Juxtaposed ligands and receptors 160Paracrine Factors : The Inducer Molecules 145
n SIDELIGHTS & SPECULATIONS: Juxtacrine Signaling and Cel lSignal Transduction Cascades : The Response to
Patterning 162Inducers 147
The extracellular matrix as a source of developmentalFibroblast growth factors and the RTK pathway 147
signals 164
The JAK-STAT pathway 150
Direct transmission of signals through gap junctions 16 7
The Hedgehog family 151
Cross-Talk between Pathways 168
The Wnt family 153
Maintenance of the Differentiated State 16 9The TGF-ß superfamily 155
Coda 17 1
PART
Early EmbryonicDevelopmen t
CHAPTER 7 Fertilization : Beginninga New Organism 175
Structure of the Gametes 175
Late responses : Resumption of protein and DNA
Sperm 175
synthesis 194
The egg 178
n SIDELIGHTS & SPECULATIONS : The Activation of Gamet eMetabolism 19 5
Recognition of egg and sperm 181
Fusion of genetic material 19 8External Fertilization in Sea Urchins 181
Mammalian Fertilization 19 9Sperm attraction : Action at a distance 181
Getting the gametes into the oviduct : Translocation andThe acrosome reaction 183
capacitation 19 9
Species-specific recognition 184
In the vicinity of the oocyte : Hyperactivation ,Fusion of the egg and sperm cell membranes 186
thermotaxis, and chemotaxis 20 1
The Prevention of Polyspermy 187
Recognition at the zona pellucida 20 2
The fast block to polyspermy 187
Gamete fusion and the prevention of polyspermy 204
The slow block to polyspermy 189
Fusion of genetic material 20 5
Calcium as the initiator of the cortical granule
Coda 20 7reaction 190
n SIDELIGHTS&SPECULATIONS :TheNonequivalenceo f
Activation of Egg Metabolism in Sea Urchins 193
Mammalian Pronuclei 207
Early responses 193
CHAPTER 8 Early Development in Selected Invertebrates 21 1EARLY DEVELOPMENTAL PROCESSES :
n SIDELIGHTS & SPECULATIONS : Adaptation by Modifyin g
AN OVERVIEW 211
Embryonic Cleavage 23 3
Cleavage 211
Gastrulation in Snails 23 7
From fertilization to cleavage 212 EARLY DEVELOPMENT IN TUNICATES 23 7
The cytoskeletal mechanisms of mitosis 213
Tunicate Cleavage 23 7Patterns of embryonic cleavage 215
The tunicate fate map 23 7
Gastrulation 215
Autonomous and conditional specification of tunicat eblastomeres 23 9
Cell Specification and Axis Formation 216
Specification of the embryonic axes 24 1EARLY DEVELOPMENT IN SEA URCHINS 217
Gastrulation in Tunicates 24 1Sea Urchin Cleavage 217
THE NEMATODE CAENORHABDITIS ELEGANS 243Blastula formation 217
Why C. elegans? 243Fate maps and the determination of sea urchin
blastomeres 217
Cleavage and Axis Formation in C. elegans 243
Sea Urchin Gastrulation 223
Rotational cleavage of the C. elegans egg 24 3
Ingression of the primary mesenchyme 223
Anterior-posterior axis formation 243
First stage of archenteron invagination 226
Formation of the dorsal-ventral and right-left axes 24 7
Second and third stages of archenteron invagination 227
Control of blastomere identity 24 7
THE EARLY DEVELOPMENT OF SNAILS 229
Integration of autonomous and conditional specification :Differentiation of the C. elegans pharynx 24 9
Cleavage in Snail Embryos 229
Gastrulation in C. elegans 249A fate map of Ilyanassa obsoleta 232
Coda 250The polar lobe : Cell determination and axis formation 23 2
CHAPTER 9 The Genetics of Axis Specification in Drosophila 253
EARLY DROSOPHILA DEVELOPMENT 253
The anterior organizing center : The Bicoid an dHunchback gradients 27 1
Fertilization 254
The terminal gene group 274Cleavage 254
Anterior-posterior axis specification : Summary 27 5The mid-blastula transition 256
Segmentation Genes 27 5Gastrulation 256
n SIDELIGHTS & SPECULATIONS: Segments and Parasegments 276
GENES THAT PATTERN THE DROSOPHILA BODY PLAN
The gap genes 27 7258
The pair-rule genes 27 8
Primary Axis Formation during Oogenesis 259
The segment polarity genes 28 1
Anterior-posterior polarity in the oocyte 259
The Homeotic Selector Genes 28 3Dorsal-ventral patterning in the oocyte 259
Patterns of homeotic gene expression 28 3
Generating Dorsal-Ventral Pattern in the Embryo 263
Initiating the patterns of homeotic gene expression 28 5
Dorsal, the ventral morphogen 263
Maintaining the patterns of homeotic gene expression 28 5
Establishing a nuclear dorsal gradient 263
Realisator genes 28 5
Effects of the dorsal protein gradient 264
n SIDELIGHTS & SPECULATIONS : The Homeodomain Proteins 28 6
Segmentation and the Anterior-Posterior Body Plan 266
Axes and Organ Primordia : The Cartesian Coordinat e
Maternal gradients : Polarity regulation by oocyte
Model 288
cytoplasm 266
Coda 288The molecular model : Protein gradients in the earl y
embryo 266
CHAPTER 10 Early Development and Axis Formation in Amphibians 29 1Early Amphibian Development 291
Mechanisms of Axis Determination in Amphibians 30 6Fertilization and cortical rotation 291
How does the organizer form? 30 6
Unequal radial holoblastic cleavage 292
Functions of the Organizer 31 2The Mid-Blastula Transition : Preparing for
Induction of neural ectoderm and dorsal mesoderm :Gastrulation 294
BMP inhibitors 31 3
Amphibian Gastrulation 295
The Regional Specificity of Induction 31 6The Xenopus fate map 295
The determination of regional differences 31 6
Vegetal rotation and the invagination of the
n SIDELIGHTS G SPECULATIONS : BMP4 and Geoffroy's Lobster 31 7bottle cells 295
The head inducer : Wnt inhibitors 31 8n SIDELIGHTS & SPECULATIONS : Fibronectin and the Pathways for
Trunk induction : Wnt signals and retinoic acid 32 0Mesodermal Migration 300
Specifying the Left-Right Axis 322Epiboly of the prospective ectoderm 30 1
Progressive Determination of the Amphibian Axes 302
Coda 322n SIDELIGHTS & SPECULATIONS : Competence, Bias, an d
Hans Spemann and Hilde Mangold : Primary
Neurulation 32 3Embryonic Induction 30 5
CHAPTER 11 The Early Development of Vertebrates:Fish, Birds, and Mammals 32 5
EARLY DEVELOPMENT IN FISH 325
EARLY MAMMALIAN DEVELOPMENT 348Cleavage in Fish Eggs 327
Cleavage in Mammals 348Gastrulation in Fish Embryos 329
The unique nature of mammalian cleavage 348
The formation of germ layers 330
Compaction 34 9
Axis Formation in Fish Embryos 331
Escape from the zona pellucida 35 1
Dorsal-ventral axis formation : The embryonic shield and
Gastrulation in Mammals 35 1Nieuwkoop center 331
Modifications for development within anothe rThe fish Nieuwkoop center 333
organism 35 2
Anterior-posterior axis formation 335
Formation of extraembryonic membranes 35 4
Left-right axis formation 335
III SIDELIGHTS & SPECULATIONS : Twins and Embryoni cStem Cells 35 6
EARLY DEVELOPMENT IN BIRDS 336Mammalian Anterior-Posterior Axis Formation 35 8
Cleavage in Bird Eggs 336
Two signaling centers 35 8Gastrulation of the Avian Embryo 337
Patterning the anterior-posterior axis: FGFs, retinoic acid ,The hypoblast 337
and the Hox code hypothesis 35 8
The primitive streak 337
Expression of Hox genes along the dorsal axis 36 1
Epiboly of the ectoderm 341
Experimental analysis of the Hox code 36 2
Axis Formation in the Chick Embryo 343
The Dorsal-Ventral and Right-Left Axes in Mice 36 4The role of gravity in forming the anterior-posterior
The dorsal-ventral axis 36 4axis 343
The left-right axis 364The chick "organizer" 343
Coda 366Left-Right Axis Formation 347
PART
Later EmbryonicDevelopmen t
CHAPTER 12 The Emergence of the Ectoderm :Central Nervous System and Epidermis 373
Establishing the Neural Cells 373
Adult neural stem cells 39 3
Formation of the Neural Tube 374
Differentiation of Neurons 39 4Primary neurulation 375
Development of the VertebrateSecondary neurulation 380
Eye 397
Differentiation of the Neural Tube 380
The dynamics of optic
The anterior-posterior axis 381
development 397
The dorsal ventral axis 383
Neural retina differentiation 39 8
Lens and cornea differentiation 400Tissue Architecture of the Central Nervous System 38 5Spinal cord and medulla organization 386
The Epidermis and the Origin of Cutaneou sStructures 400
Cerebellar organization 387
The origin of epidermal cells 40 0Cerebral organization 388
Cutaneous appendages 402n SIDELIGHTS ti SPECULATIONS : The Unique Development of the
The follicular stem cell 404Human Brain 39 1
CHAPTER 13 Neural Crest Cells and Axonal Specificity 40 7
THE NEURAL CREST 407
NEURONAL SPECIFICATION AND AXONA LSpecification of the Neural Crest Cells 407
SPECIFICITY 42 4
Regionalization of the neural crest 409
The Generation of Neuronal Diversity 42 4
Trunk Neural Crest 409
Pattern Generation in the Nervous System 426Migration pathways of trunk neural crest cells 409
Cell adhesion and contact guidance by attractive and
The mechanisms of trunk neural crest migration 411
permissive molecules 42 7Guidance by specific growth cone repulsion 42 7
The Pluripotency of Neural Crest Cells 414
Guidance by diffusible molecules 42 9Cranial Neural Crest 417
Target selection 432n SIDELIGHTS G SPECULATIONS : Cranial Neural Crest Cell
Forming the synapse : Activity-dependent development 43 2Migration and Specification 41 8Intramembranous ossification 420
Differential survival after innervation : Neurotrophicfactors 43 5
Tooth formation 421
Paths to glory : Migration of the retinal ganglion axons 43 6Cardiac Neural Crest 422
The Development of Behaviors: Constancy an dCranial Placodes 422
Plasticity 440
CHAPTER 14 Paraxial and Intermediate Mesoderm 44 3
PARAXIAL MESODERM: THE SOMITES AND THEIR
Where somites form : The Notch pathway 446
DERIVATIVES 444
The separation of somites from the unsegmente d
The Formation of Somites 445
mesoderm 44 8
The periodicity of somite formation 445
n SIDELIGHTS C, SPECULATIONS : Coordinating Waves and Clocksin Somite Formation 448
Epithelialization of the somites 449
Vertebrae formation 45 7Somite specification along the anterior-posterior axis 450
Tendon formation : The syndetome 45 8Derivatives of the somites 450
INTERMEDIATE MESODERM : THE UROGENITA LDetermination of the sclerotome and dermatome 452
SYSTEM 46 0Determination of the myotome 452
Specification of the Intermediate Mesoderm : Pax2/8Myogenesis : The Generation of Muscle 453
and Lim1 460Specification and differentiation by myogenic bHLH
Progression of Kidney Types 46 1proteins 453
Reciprocal Interactions of Developing KidneyMuscle cell fusion 453
Tissues 46 2Osteogenesis: The Development of Bones 455
The mechanisms of reciprocal induction 46 3Endochondral ossification 45 5
CHAPTER 15 Lateral Plate Mesoderm and Endoderm 471
LATERAL PLATE MESODERM 471
The Development of Blood Cells 48 9The Heart 472
The stem cell concept 489
Specification of heart tissue 472
Sites of hematopoiesis 490
Fusion of the heart rudiments and initial heartbeats 477
Committed stem cells and their fates 49 1
Looping and formation of heart chambers 478
Hematopoietic inductive microenvironments 49 3
n SIDELIGHTS &SPECULATIONS : Redirecting Blood Flow in the
ENDODERM 493Newborn Mammal 480
The Pharynx 49 5Formation of Blood Vessels 482
The Digestive Tube and Its Derivatives 49 5Constraints on the construction of blood vessels 482
Specification of the gut tissue 49 6Vasculogenesis: The initial formation of blood vessels 483
Liver, pancreas, and gallbladder 497Angiogenesis: Sprouting of blood vessels and remodeling
• SIDELIGHTS b SPECULATIONS : Blood and Guts : The Specificatio nof vascular beds 485
of Liver and Pancreas 49 8Arterial and venous differentiation 486
The Respiratory Tube 50 0Organ-specific angiogenesis factors 48 7
The lymphatic vessels 489
The Extraembryonic Membranes 50 1The amnion and chorion 50 1
The allantois and yolk sac 50 2
CHAPTER 16 Development of the Tetrapod Limb 50 5
Formation of the Limb Bud 506
Specifying digit identity by Sonic hedgehog 51 8
Specification of the limb fields 506
n SIDELIGHTS & SPECULATIONS : Hox Gene Changes durin g
Induction of the early limb bud : Wnt proteins and
Development and Formation of the ZPA 51 8
fibroblast growth factors 507
Generation of the Dorsal-Ventral Axis 51 9Specification of forelimb or hindlimb : Tbx4 and Tbx5
Coordinating the Three Axes 52 0508
Cell Death and the Formation of Digits and Joints 52 2Generating the Proximal-Distal Axis of the Limb 509
Sculpting the autopod 52 2The apical ectodermal ridge 509
n SIDELIGHTS S SPECULATIONS : Limb Development an dFGFs in the induction and maintenance of the AER 512
Evolution 523
Specifying the limb mesoderm : Determining the
Forming the joints 52 4proximal-distal polarity of the limb 512
n SIDELIGHTS b SPECULATIONS : Continued Limb Growth :The Hox specification code for the limb 514
Epiphyseal Plates 52 5
Specification of the Anterior-Posterior Limb Axis 515
Coda 526The zone of polarizing activity 515
CHAPTER 17 Sex Determination 529
Historical Views on Sex Determination 529
III SIDELIGHTS G SPECULATIONS : Sex Determination an dCHROMOSOMAL SEX DETERMINATION 530
Behaviors 542
The Mammalian Pattern: Primary and Secondary Sex
Chromosomal Sex Determination in Drosophila 543Determination 530
The gene cascade of Drosophila sex determination 544
Primary Sex Determination 531
The Sex-lethal gene as the pivot for sex determination 54 4
The developing gonads 531
Doublesex: The switch gene of sex determination 54 7
Mechanisms of primary sex determination 532
Brain Sex in Drosophila: Secondary Sex Determinatio n
The right time and the right place 538 through another Pathway 54 9
Secondary Sex Determination in Mammals : Hormonal
Dosage Compensation 550
Regulation of the Sexual Phenotype 539
ENVIRONMENTAL SEX DETERMINATION 55 0Testosterone and dihydrotestosterone 540
Temperature-Dependent Sex Determination i nAnti-Müllerian hormone 541
Reptiles 550Estrogen 541
Aromatase and cell proliferation during se x
Brain sex: Secondary sex determination through another
determination 55 1
pathway? 541
Sex reversal, aromatase, and conservation biology 55 1
Location-Dependent Sex Determination 552
CHAPTER 18 Postembryonic Development: Metamorphosis, Regeneration,and Aging 555
METAMORPHOSIS : THE HORMONAL REACTIVATION
Proliferation of the blastema cells : The requirement fo rOF DEVELOPMENT 555
FgflO 57 5
Amphibian Metamorphosis 556
A two-step model 57 7
Morphological changes associated with
II SIDELIGHTS &SPECULATIONS : Pattern Formation in th emetamorphosis 556
Regeneration Blastema 57 8
Hormonal control of amphibian metamorphosis 558
Morphallactic Regeneration in Hydra 580
Regionally specific developmental programs 561
The head activation gradient 580
n SIDELIGHTS G SPECULATIONS : Variations on the Theme of
The head inhibition gradient 58 1Amphibian Metamorphosis 562
The hypostome as an " organizer" 58 2
Metamorphosis in Insects 564
The basal disc activation and inhibition gradients 58 3Imaginal discs 564
Compensatory Regeneration in the Mammalia nDetermination of the wing imaginal discs 568
Liver 584Hormonal control of insect metamorphosis 569
AGING: THE BIOLOGY OF SENESCENCE 58 5The molecular biology of 20-hydroxyecdysone activity 571
Maximum Life Span and Life Expectancy 58 5REGENERATION 573
Causes of aging 58 6
Epimorphic Regeneration of Salamander Limbs 574
Genetically regulated aging: The insulin pathway 58 8
Formation of the apical ectodermal cap and regeneration
Promoting longevity 59 0blastema 574
n SIDELIGHTS S SPECULATIONS : Aging : Exceptions to th eProliferation of the blastema cells : The requirement for
Rule 590nerves 57 5
CHAPTER 19 The Saga of the Germ Line 593
Germ Plasm and the Determination of the Primordial
Germ cell determination in insects 59 5Germ Cells 593
Germ cell determination in frogs and fish 59 8Germ cell determination in nematodes 594
Germ cell determination in mammals 598
nSIDELIGHTS G SPECULATIONS : Pluripotency, Germ Cells, and Spermatogenesis in Mammals 61 2Embryonic Stem Cells 599
Forming the haploid spermatid 61 2The inert genome hypothesis 602
Spermiogenesis : The differentiation of the sperm 61 4Germ Cell Migration 602
Oogenesis 61 5Germ cell migration in Drosophila 602
Oogenic meiosis 61 5Germ cell migration in vertebrates 603
Maturation of the oocytes in frogs 61 6Meiosis 606
Gene transcription in amphibian oocytes 61 8n SIDELIGHTS G SPECULATIONS : Big Decisions: Mitosis or Meiosis? Meroistic oogenesis in insects 61 9
Sperm or Egg? 610Maturation of the mammalian oocyte 620
Coda 622
PART
Ramifications of4 Developmental BiologyCHAPTER 20 An Overview of
Plant Development 627
Gamete Production in Angiosperms 628
Root development 64 3
Gametophytes 628
Shoot development 64 3
Pollination 630
Leaf development 644
Fertilization 633
The Vegetative-to-Reproductive Transition 647
Embryonic Development 634
Juvenility 64 8
Embryogenesis 634
Floral signals 64 9
Dormancy 639
Inflorescence development 650Floral meristem identity 65 0
Germination 640Senescence 65 3
Vegetative Growth 64 1Meristems 64 1
CHAPTER 21 Medical Implications of Developmental Biology 65 5
GENETIC ERRORS OF HUMAN DEVELOPMENT 655
In Vitro Fertilization 663
Identifying the Genes for Human Developmental
The IVF procedure 66 3
Anomalies 657
Success rates and complications of IVF 66 4
The Nature of Human Syndromes 659
n SIDELIGHTS G SPECULATIONS : Prenatal Diagnosis an dPreimplantation Genetics 66 5
Pleiotropy 659
TERATOGENESIS : ENVIRONMENTAL ASSAULTS O NGeneti c ic heterogeneity 659
HUMAN DEVELOPMENT 666Phenotypic variability 659
Mechanisms of dominance 660
Teratogenic Agents 66 7
Alcohol as a teratogen 66 7Gene Expression and Human Disease 66 1
Inborn errors of nuclear RNA processing 661Retinoic acid as a teratogen 66 8Other teratogenic agents 67 0
Inborn errors of translation 662
Endocrine disruptors and human development 67 0INFERTILITY 663
Testicular dysgenesis and declining sperm counts 67 3Diagnosing Infertility 663
n SIDELIGHTS & SPECULATIONS: Bisphenol-A: Potencies and
Gene Therapy 68 1Politics 674
Germline Gene Therapy 683DEVELOPMENTAL BIOLOGY AND THE FUTURE O F
MEDICINE 675
Stem Cells and Therapeutic Cloning 68 4
Developmental Cancer Therapies 675 Embryonic stem cells and therapeutic cloning 68 4Multipotent adult stem cells 68 7n SIDELIGHTS & SPECULATIONS : The Embryonic Origins of Adult -
Onset Illnesses 676
Pluripotent adult stem cells 68 8
Cancer as a disease of altered development 677
Transgenic stem cells 68 8
n SIDELIGHTS &SPECULATIONS : Differentiation Therapy 679
Regeneration therapy 68 9Angiogenesis inhibition 680
CHAPTER 22 Environmental Regulation of Animal Development 69 3Phenotypic Plasticity 693
Polyphenisms for alternative environmenta l
The Environment as Part of Normal Development 695
conditions 70 6
Gravity and pressure 695 Predator-induced polyphenisms 707
Developmental symbiosis 696
Learning: The Environmentally Adaptive Nervous
Larval settlement 698
System 709
Sex in its season 699
The formation of new neurons 709
Diapause : Suspended development 700
Experiential changes in mammalian visual pathways 71 0
Polyphenisms and Plasticity 701
Endocrine Disruptors 71 2
Seasonal polyphenism in lepidopterans 701 Environmental estrogens 71 2
Nutritional polyphenism 703 Environmental thyroid hormone disruptors 71 4
Diet and DNA methylation 704 Chains of causation 71 4
Environment-dependent sexual phenotype 705 n SIDELIGHTS & SPECULATIONS: Deformed Frogs 71 7
II SIDELIGHTS & SPECULATIONS : Fetal DNA Methylation and Adult
Developmental Biology Meets the Real World 71 8Behavior 70 5
CHAPTER 23 Developmental Mechanisms of Evolutionary Change 72 1
"Unity of Type" and "Conditions of Existence" 721
Heterometry 73 7Charles Darwin 's synthesis 721
Heterotypy 73 9
"Life's splendid drama" 722
Recruitment 74 0
Preconditions for Macroevolution through
II SIDELIGHTS & SPECULATIONS : Nature's Experiments : Coding
Developmental Change 723
Tandem Repeats 740
Modularity: Divergence through dissociation 723
II SIDELIGHTS & SPECULATIONS: How the Chordates Got a Hea d74 2
Molecular parsimony : Gene duplication and diversion 725Developmental Constraints 744
n SIDELIGHTS & SPECULATIONS: The Search for the Urbilateria nAncestor 726
Physical constraints 744
Homologous Pathways of Development 730
Morphogenetic constraints 74 4
Mechanisms of Macroevolutionary Change 731
Phyletic constraints 74 5n SIDELIGHTS & SPECULATIONS : Canalization and the Release o f
Heterotopy 731
Developmental Constraints 74 7Heterochrony 735
A New Evolutionary Synthesis 74 8
ILLUSTRATION SOURCES 75 3
AUTHOR INDEX 76 9
SUBJECT INDEX 785