Concepts of genetics

Cover......Page 1
Title Page......Page 5
Copyright Page......Page 6
About the Authors......Page 7
Conceptual Understanding......Page 10
New and Updated Content......Page 11
Problem Solving......Page 12
NEW! Practice Problem-Solving with MasteringGenetics\n......Page 13
Active and Cooperative Learning......Page 14
Contents......Page 15
Preface......Page 32
Acknowledgments......Page 38
1 Introduction to Genetics......Page 41
1.1 Genetics Has a Rich and Interesting History......Page 42
1.2 Genetics Progressed from Mendel to DNA in Less Than a Century......Page 44
1.3 Discovery of the Double Helix Launched the Era of Molecular Genetics......Page 46
1.4 Development of Recombinant DNA Technology Began the Era of Cloning......Page 48
1.5 The Impact of Biotechnology Is Continually Expanding......Page 49
1.7 Genetic Studies Rely on the Use of Model Organisms......Page 52
1.8 We Live in the Age of Genetics......Page 54
GENETICS, TECHNOLOGY, AND SOCIETY: The Scientific and Ethical Implications of Modern Genetics......Page 55
EXPLORING GENOMICS: Internet Resources for Learning about Genomics, Bioinformatics, and Proteomics......Page 56
Problems and Discussion Questions......Page 57
2 Mitosis and Meiosis......Page 58
2.1 Cell Structure Is Closely Tied to Genetic Function......Page 59
2.2 Chromosomes Exist in Homologous Pairs in Diploid Organisms......Page 61
2.3 Mitosis Partitions Chromosomes into Dividing Cells......Page 63
2.4 Meiosis Reduces the Chromosome Number from Diploid to Haploid in Germ Cells and Spores......Page 68
2.5 The Development of Gametes Varies in Spermatogenesis Compared to Oogenesis......Page 73
2.7 Electron Microscopy Has Revealed the Physical Structure of Mitotic and Meiotic Chromosomes......Page 75
CASE STUDY: Timing is everything......Page 77
Insights and Solutions......Page 78
Problems and Discussion Questions......Page 79
3 Mendelian Genetics......Page 82
3.2 The Monohybrid Cross Reveals How One Trait Is Transmitted from Generation to Generation......Page 83
3.3 Mendel’s Dihybrid Cross Generated a Unique F[sub(2)] Ratio......Page 88
3.4 The Trihybrid Cross Demonstrates That Mendel’s Principles Apply to Inheritance of Multiple Traits......Page 89
How Mendel’s Peas Become Wrinkled: A Molecular Explanation......Page 91
3.5 Mendel’s Work Was Rediscovered in the Early Twentieth Century......Page 93
3.6 Independent Assortment Leads to Extensive Genetic Variation......Page 95
Tay–Sachs Disease: The Molecular Basis of a Recessive Disorder in Humans......Page 96
3.8 Chi-Square Analysis Evaluates the Influence of Chance on Genetic Data......Page 98
3.9 Pedigrees Reveal Patterns of Inheritance of Human Traits......Page 101
CASE STUDY: To test or not to test......Page 104
Insights and Solutions......Page 105
Problems and Discussion Questions......Page 107
4 Extensions of Mendelian Genetics......Page 111
4.1 Alleles Alter Phenotypes in Different Ways......Page 112
4.2 Geneticists Use a Variety of Symbols for Alleles......Page 113
4.4 In Codominance, the Influence of Both Alleles in a Heterozygote Is Clearly Evident......Page 114
4.5 Multiple Alleles of a Gene May Exist in a Population......Page 115
4.6 Lethal Alleles Represent Essential Genes......Page 117
4.7 Combinations of Two Gene Pairs with Two Modes of Inheritance Modify the 9:3:3:1 Ratio......Page 118
The Molecular Basis of Dominance and Recessiveness: The Agouti Gene......Page 119
4.9 Complementation Analysis Can Determine If Two Mutations Causing a Similar Phenotype Are Alleles of the Same Gene......Page 126
4.10 Expression of a Single Gene May Have Multiple Effects......Page 127
4.11 X-Linkage Describes Genes on the X Chromosome......Page 128
4.12 In Sex-Limited and Sex-Influenced Inheritance, an Individual’s Sex Influences the Phenotype......Page 130
4.13 Genetic Background and the Environment May Alter Phenotypic Expression......Page 131
GENETICS, TECHNOLOGY, AND SOCIETY: Improving the Genetic Fate of Purebred Dogs......Page 135
Summary Points......Page 136
Insights and Solutions......Page 137
Problems and Discussion Questions......Page 139
5 Chromosome Mapping in Eukaryotes......Page 145
5.1 Genes Linked on the Same Chromosome Segregate Together......Page 146
5.2 Crossing Over Serves as the Basis for Determining the Distance between Genes in Chromosome Mapping......Page 149
5.3 Determining the Gene Sequence during Mapping Requires the Analysis of Multiple Crossovers......Page 152
5.4 As the Distance between Two Genes Increases, Mapping Estimates Become More Inaccurate......Page 160
5.5 Drosophila Genes Have Been Extensively Mapped......Page 162
5.6 Lod Score Analysis and Somatic Cell Hybridization Were Historically Important in Creating Human Chromosome Maps......Page 163
5.7 Chromosome Mapping Is Now Possible Using DNA Markers and Annotated Computer Databases......Page 164
5.8 Crossing Over Involves a Physical Exchange between Chromatids......Page 165
5.9 Exchanges Also Occur between Sister Chromatids......Page 166
5.10 Linkage and Mapping Studies Can Be Performed in Haploid Organisms......Page 167
5.11 Did Mendel Encounter Linkage?......Page 173
CASE STUDY: Links to autism......Page 174
Insights and Solutions......Page 175
Problems and Discussion Questions......Page 177
6 Genetic Analysis and Mapping in Bacteria and Bacteriophages......Page 183
6.1 Bacteria Mutate Spontaneously and Grow at an Exponential Rate......Page 184
6.2 Genetic Recombination Occurs in Bacteria......Page 185
6.4 The F Factor Is an Example of a Plasmid......Page 193
6.5 Transformation Is a Second Process Leading to Genetic Recombination in Bacteria......Page 194
6.6 Bacteriophages Are Bacterial Viruses......Page 196
6.7 Transduction Is Virus-Mediated Bacterial DNA Transfer......Page 199
6.8 Bacteriophages Undergo Intergenic Recombination......Page 201
6.9 Intragenic Recombination Occurs in Phage T4......Page 202
GENETICS, TECHNOLOGY, AND SOCIETY: From Cholera Genes to Edible Vaccines......Page 207
Summary Points......Page 208
Insights and Solutions......Page 209
Problems and Discussion Questions......Page 210
7 Sex Determination and Sex Chromosomes......Page 214
7.1 Life Cycles Depend on Sexual Differentiation......Page 215
7.2 X and Y Chromosomes Were First Linked to Sex Determination Early in the Twentieth Century......Page 218
7.3 The Y Chromosome Determines Maleness in Humans......Page 219
7.4 The Ratio of Males to Females in Humans Is Not 1.0......Page 224
7.5 Dosage Compensation Prevents Excessive Expression of X-Linked Genes in Mammals......Page 225
7.6 The Ratio of X Chromosomes to Sets of Autosomes Determines Sex in Drosophila......Page 229
7.7 Temperature Variation Controls Sex Determination in Reptiles......Page 232
GENETICS, TECHNOLOGY, AND SOCIETY: A Question of Gender: Sex Selection in Humans......Page 233
Insights and Solutions......Page 234
Problems and Discussion Questions......Page 235
8 Chromosome Mutations: Variation in Number and Arrangement......Page 237
8.1 Variation in Chromosome Number: Terminology and Origin......Page 238
8.2 Monosomy and Trisomy Result in a Variety of Phenotypic Effects......Page 239
8.3 Polyploidy, in Which More Than Two Haploid Sets of Chromosomes Are Present, Is Prevalent in Plants......Page 243
8.4 Variation Occurs in the Composition and Arrangement of Chromosomes......Page 246
8.5 A Deletion Is a Missing Region of a Chromosome......Page 247
8.6 A Duplication Is a Repeated Segment of a Chromosome......Page 248
Copy Number Variants (CNVs)—Duplications and Deletions at the Molecular Level......Page 250
8.7 Inversions Rearrange the Linear Gene Sequence......Page 251
8.8 Translocations Alter the Location of Chromosomal Segments in the Genome......Page 252
8.9 Fragile Sites in Human Chromosomes Are Susceptible to Breakage......Page 254
EXPLORING GENOMICS: Atlas of Genetics and Cytogenetics in Oncology and Haematology......Page 256
Summary Points......Page 257
Problems and Discussion Questions......Page 258
9 Extranuclear Inheritance......Page 261
9.1 Organelle Heredity Involves DNA in Chloroplasts and Mitochondria......Page 262
9.2 Knowledge of Mitochondrial and Chloroplast DNA Helps Explain Organelle Heredity......Page 265
9.3 Mutations in Mitochondrial DNA Cause Human Disorders......Page 269
9.4 In Maternal Effect, the Maternal Genotype Has a Strong Influence during Early Development......Page 271
GENETICS, TECHNOLOGY, AND SOCIETY: Mitochondrial DNA and the Mystery of the Romanovs......Page 273
Insights and Solutions......Page 275
Problems and Discussion Questions......Page 276
10 DNA Structure and Analysis......Page 278
10.1 The Genetic Material Must Exhibit Four Characteristics......Page 279
10.3 Evidence Favoring DNA as the Genetic Material Was First Obtained during the Study of Bacteria and Bacteriophages......Page 280
10.4 Indirect and Direct Evidence Supports the Concept that DNA Is the Genetic Material in Eukaryotes......Page 286
10.6 Knowledge of Nucleic Acid Chemistry Is Essential to the Understanding of DNA Structure......Page 287
10.7 The Structure of DNA Holds the Key to Understanding Its Function......Page 290
Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid......Page 295
10.8 Alternative Forms of DNA Exist......Page 296
10.9 The Structure of RNA Is Chemically Similar to DNA, but Single Stranded......Page 297
10.10 Many Analytical Techniques Have Been Useful during the Investigation of DNA and RNA......Page 298
EXPLORING GENOMICS: Introduction to Bioinformatics: BLAST......Page 304
Insights and Solutions......Page 305
Problems and Discussion Questions......Page 306
11 DNA Replication and Recombination......Page 309
11.1 DNA Is Reproduced by Semiconservative Replication......Page 310
11.2 DNA Synthesis in Bacteria Involves Five Polymerases, as Well as Other Enzymes......Page 314
11.3 Many Complex Issues Must Be Resolved during DNA Replication......Page 317
11.4 A Coherent Model Summarizes DNA Replication......Page 320
11.6 Eukaryotic DNA Replication Is Similar to Replication in Prokaryotes, But Is More Complex......Page 321
11.7 The Ends of Linear Chromosomes Are Problematic during Replication......Page 324
11.8 DNA Recombination, Like DNA Replication, Is Directed by Specific Enzymes......Page 326
GENETICS, TECHNOLOGY, AND SOCIETY: Telomeres: The Key to Immortality?......Page 329
Insights and Solutions......Page 330
Problems and Discussion Questions......Page 331
12 DNA Organization in Chromosomes......Page 334
12.1 Viral and Bacterial Chromosomes Are Relatively Simple DNA Molecules......Page 335
12.2 Supercoiling Facilitates Compaction of the DNA of Viral and Bacterial Chromosomes......Page 337
12.3 Specialized Chromosomes Reveal Variations in the Organization of DNA......Page 338
12.4 DNA Is Organized into Chromatin in Eukaryotes......Page 340
12.5 Chromosome Banding Differentiates Regions along the Mitotic Chromosome......Page 344
12.6 Eukaryotic Genomes Demonstrate Complex Sequence Organization Characterized by Repetitive DNA......Page 346
12.7 The Vast Majority of a Eukaryotic Genome Does Not Encode Functional Genes......Page 349
EXPLORING GENOMICS: Database of Genomic Variants: Structural Variations in the Human Genome......Page 350
Insights and Solutions......Page 351
Problems and Discussion Questions......Page 352
13 The Genetic Code and Transcription......Page 355
13.1 The Genetic Code Uses Ribonucleotide Bases as “Letters”......Page 356
13.2 Early Studies Established the Basic Operational Patterns of the Code......Page 357
13.3 Studies by Nirenberg, Matthaei, and Others Led to Deciphering of the Code......Page 358
13.4 The Coding Dictionary Reveals Several Interesting Patterns among the 64 Codons......Page 363
13.6 The Genetic Code Is Nearly Universal......Page 365
13.7 Different Initiation Points Create Overlapping Genes......Page 366
13.9 Studies with Bacteria and Phages Provided Evidence for the Existence of mRNA......Page 367
13.10 RNA Polymerase Directs RNA Synthesis......Page 368
13.11 Transcription in Eukaryotes Differs from Prokaryotic Transcription in Several Ways......Page 370
13.12 The Coding Regions of Eukaryotic Genes Are Interrupted by Intervening Sequences......Page 373
13.13 RNA Editing May Modify the Final Transcript......Page 376
13.14 Transcription Has Been Visualized by Electron Microscopy......Page 377
Summary Points......Page 378
GENETICS, TECHNOLOGY, AND SOCIETY: Nucleic Acid-Based Gene Silencing: Attacking the Messenger......Page 379
Problems and Discussion Questions......Page 380
14 Translation and Proteins......Page 384
14.1 Translation of mRNA Depends on Ribosomes and Transfer RNAs......Page 385
14.2 Translation of mRNA Can Be Divided into Three Steps......Page 389
14.3 High-Resolution Studies Have Revealed Many Details about the Functional Prokaryotic Ribosome......Page 392
14.4 Translation Is More Complex in Eukaryotes......Page 393
14.5 The Initial Insight That Proteins Are Important in Heredity Was Provided by the Study of Inborn Errors of Metabolism......Page 394
14.6 Studies of Neurospora Led to the One-Gene: One-Enzyme Hypothesis......Page 396
14.7 Studies of Human Hemoglobin Established That One Gene Encodes One Polypeptide......Page 398
14.9 Variation in Protein Structure Provides the Basis of Biological Diversity......Page 401
14.10 Posttranslational Modification Alters the Final Protein Product......Page 405
14.11 Proteins Function in Many Diverse Roles......Page 406
14.12 Proteins Are Made Up of One or More Functional Domains......Page 407
EXPLORING GENOMICS: Translation Tools and Swiss-Prot for Studying Protein Sequences......Page 409
Insights and Solutions......Page 410
Problems and Discussion Questions......Page 411
15 Gene Mutation, DNA Repair, and Transposition......Page 414
15.1 Gene Mutations Are Classified in Various Ways......Page 415
15.2 Spontaneous Mutations Arise from Replication Errors and Base Modifications......Page 419
15.3 Induced Mutations Arise from DNA Damage Caused by Chemicals and Radiation......Page 421
15.4 Single-Gene Mutations Cause a Wide Range of Human Diseases......Page 424
15.5 Organisms Use DNA Repair Systems to Counteract Mutations......Page 426
15.6 The Ames Test Is Used to Assess the Mutagenicity of Compounds......Page 432
15.7 Geneticists Use Mutations to Identify Genes and Study Gene Function......Page 433
15.8 Transposable Elements Move within the Genome and May Create Mutations......Page 434
EXPLORING GENOMICS: Sequence Alignment to Identify a Mutation......Page 438
Summary Points......Page 439
Problems and Discussion Questions......Page 440
16 Regulation of Gene Expression in Prokaryotes......Page 443
16.2 Lactose Metabolism in E. coli Is Regulated by an Inducible System......Page 444
16.3 The Catabolite-Activating Protein (CAP) Exerts Positive Control over the lac Operon......Page 450
16.4 Crystal Structure Analysis of Repressor Complexes Has Confirmed the Operon Model......Page 452
16.5 The Tryptophan (trp) Operon in E. coli Is a Repressible Gene System......Page 453
16.6 Attenuation Is a Process Critical to the Regulation of the trp Operon in E. coli......Page 455
16.7 Riboswitches Utilize Metabolite-sensing RNAs to Regulate Gene Expression......Page 458
16.8 The ara Operon Is Controlled by a Regulator Protein That Exerts Both Positive and Negative Control......Page 459
Summary Points......Page 460
GENETICS, TECHNOLOGY, AND SOCIETY: Quorum Sensing: Social Networking in the Bacterial World......Page 461
Problems and Discussion Questions......Page 462
17 Regulation of Gene Expression in Eukaryotes......Page 466
17.1 Eukaryotic Gene Regulation Can Occur at Any of the Steps Leading from DNA to Protein Product......Page 467
17.2 Programmed DNA Rearrangements Regulate Expression of a Small Number of Genes......Page 468
17.3 Eukaryotic Gene Expression Is Influenced by Chromatin Modifications......Page 470
17.4 Eukaryotic Transcription Initiation Is Regulated at Specific Cis-Acting Sites......Page 472
17.5 Eukaryotic Transcription Initiation Is Regulated by Transcription Factors that Bind to Cis-Acting Sites......Page 474
17.6 Activators and Repressors Interact with General Transcription Factors at the Promoter......Page 476
17.7 Gene Regulation in a Model Organism: Transcription of the GAL Genes of Yeast......Page 477
17.8 Posttranscriptional Gene Regulation Occurs at All the Steps from RNA Processing to Protein Modification......Page 479
17.9 RNA Silencing Controls Gene Expression in Several Ways......Page 483
EXPLORING GENOMICS: Tissue-Specific Gene Expression......Page 485
Summary Points......Page 486
Insights and Solutions......Page 487
Problems and Discussion Questions......Page 488
18 Developmental Genetics......Page 491
18.1 Differentiated States Develop from Coordinated Programs of Gene Expression......Page 492
18.3 Genetic Analysis of Embryonic Development in Drosophila Reveals How the Animal Body Axis Is Specified......Page 493
18.4 Zygotic Genes Program Segment Formation in Drosophila......Page 496
18.5 Homeotic Selector Genes Specify Parts of the Adult Body......Page 498
18.6 Plants Have Evolved Developmental Systems That Parallel Those of Animals......Page 502
18.7 Cell–Cell Interactions in Development Are Modeled in C. elegans......Page 504
18.8 Programmed Cell Death Is Required for Normal Development......Page 507
GENETICS, TECHNOLOGY, AND SOCIETY: Stem Cell Wars......Page 508
Summary Points......Page 509
Problems and Discussion Questions......Page 510
19 Cancer and Regulation of the Cell Cycle......Page 513
19.1 Cancer Is a Genetic Disease at the Level of Somatic Cells......Page 514
19.2 Cancer Cells Contain Genetic Defects Affecting Genomic Stability, DNA Repair, and Chromatin Modifications......Page 516
19.3 Cancer Cells Contain Genetic Defects Affecting Cell-Cycle Regulation......Page 518
19.4 Proto-oncogenes and Tumor-suppressor Genes Are Altered in Cancer Cells......Page 521
19.6 Predisposition to Some Cancers Can Be Inherited......Page 525
19.7 Viruses Contribute to Cancer in Both Humans and Animals......Page 527
19.8 Environmental Agents Contribute to Human Cancers......Page 528
Summary Points......Page 529
Insights and Solutions......Page 530
Problems and Discussion Questions......Page 531
SPECIAL TOPICS IN MODERN GENETICS I: DNA Forensics......Page 533
BOX 1 The Pitchfork Case: The First Criminal Conviction Using DNA Profiling......Page 534
Autosomal STR DNA Profiling......Page 535
Y-Chromosome STR Profiling......Page 537
Mitochondrial DNA Profiling......Page 538
Single-Nucleotide Polymorphism Profiling......Page 539
Interpreting DNA Profiles......Page 540
The Prosecutor’s Fallacy......Page 541
Technical and Ethical Issues Surrounding DNA Profiling......Page 542
Selected Readings and Resources......Page 543
SPECIAL TOPICS IN MODERN GENETICS II: Genomics and Personalized Medicine......Page 544
Optimizing Drug Therapies......Page 545
BOX 1 The Story of Pfizer’s Crizotinib......Page 546
Reducing Adverse Drug Reactions......Page 548
Personalized Medicine and Disease Diagnosis......Page 550
BOX 2 The Pharmacogenomics Knowledge Base (PharmGKB): Genes, Drugs, and Diseases on the Web......Page 551
Analyzing One Personal Genome......Page 553
BOX 3 How to Sequence a Human Genome......Page 554
Technical, Social, and Ethical Challenges......Page 555
Selected Readings and Resources......Page 556
SPECIAL TOPICS IN MODERN GENETICS III: Epigenetics......Page 557
Methylation......Page 559
RNA Interference......Page 560
Epigenetics and Imprinting......Page 561
Epigenetics and Cancer......Page 563
BOX 2 What More We Need to Know about Epigenetics and Cancer......Page 565
Epigenetics and the Environment......Page 566
Epigenome Projects......Page 567
Selected Readings and Resources......Page 568
What Are Stem Cells?......Page 569
Sources and Types of Stem Cells......Page 570
Cancer Stem Cells......Page 572
Tests for Pluripotency......Page 573
Nuclear Reprogramming Approaches for Producing Pluripotent Stem Cells......Page 574
Induced Pluripotent Stem Cells......Page 575
Potential Applications of Stem Cells......Page 577
iPSCs for Treating Sickle-Cell Disease......Page 580
Therapeutic Cloning......Page 581
Stem Cell Regulations......Page 582
Ethical Issues Involving Stem Cells......Page 583
Selected Resources......Page 584
20 Recombinant DNA Technology......Page 585
20.1 Recombinant DNA Technology Began with Two Key Tools: Restriction Enzymes and DNA Cloning Vectors......Page 586
20.2 DNA Libraries Are Collections of Cloned Sequences......Page 592
20.3 The Polymerase Chain Reaction Is a Powerful Technique for Copying DNA......Page 594
20.4 Molecular Techniques for Analyzing DNA......Page 599
20.5 DNA Sequencing Is the Ultimate Way to Characterize DNA Structure at the Molecular Level......Page 603
EXPLORING GENOMICS: Manipulating Recombinant DNA: Restriction Mapping and Designing PCR Primers......Page 608
Insights and Solutions......Page 610
Problems and Discussion Questions......Page 611
21 Genomics, Bioinformatics, and Proteomics......Page 614
21.1 Whole-Genome Shotgun Sequencing Is a Widely Used Method for Sequencing and Assembling Entire Genomes......Page 615
21.2 DNA Sequence Analysis Relies on Bioinformatics Applications and Genome Databases......Page 620
21.3 Functional Genomics Attempts to Identify Potential Functions of Genes and Other Elements in a Genome......Page 624
21.4 The Human Genome Project Revealed Many Important Aspects of Genome Organization in Humans......Page 626
21.5 The “Omics” Revolution Has Created a New Era of Biological Research......Page 631
21.6 Comparative Genomics Analyzes and Compares Genomes from Different Organisms......Page 634
21.7 Metagenomics Applies Genomics Techniques to Environmental Samples......Page 642
21.8 Transcriptome Analysis Reveals Profiles of Expressed Genes in Cells and Tissues......Page 643
21.9 Proteomics Identifies and Analyzes the Protein Composition of Cells......Page 646
21.10 Systems Biology Is an Integrated Approach to Studying Interactions of All Components of an Organism’s Cells......Page 652
EXPLORING GENOMICS: Contigs, Shotgun Sequencing, and Comparative Genomics......Page 655
Summary Points......Page 657
Problems and Discussion Questions......Page 658
22 Applications and Ethics of Genetic Engineering and Biotechnology......Page 661
22.1 Genetically Engineered Organisms Synthesize a Wide Range of Biological and Pharmaceutical Products......Page 662
22.2 Genetic Engineering of Plants Has Revolutionized Agriculture......Page 666
22.3 Transgenic Animals with Genetically Enhanced Characteristics Have the Potential to Serve Important Roles in Biotechnology......Page 670
22.4 Synthetic Genomes, Genome Transplantation, and the Emergence of Synthetic Biology......Page 672
22.5 Genetic Engineering and Genomics Are Transforming Medical Diagnosis......Page 674
22.6 Genome-Wide Association Studies Identify Genome Variations that Contribute to Disease......Page 684
22.7 Genomics Leads to New, More Targeted Medical Treatment Including Personalized Medicine and Gene Therapy......Page 686
22.8 Genetic Engineering, Genomics, and Biotechnology Create Ethical, Social, and Legal Questions......Page 691
GENETICS, TECHNOLOGY, AND SOCIETY: Personal Genome Projects and the Race for the $1000 Genome......Page 694
Summary Points......Page 695
Insights and Solutions......Page 696
Problems and Discussion Questions......Page 697
23 Quantitative Genetics and Multifactorial Traits......Page 699
23.2 Quantitative Traits Can Be Explained in Mendelian Terms......Page 700
23.3 The Study of Polygenic Traits Relies on Statistical Analysis......Page 703
23.4 Heritability Values Estimate the Genetic Contribution to Phenotypic Variability......Page 706
23.4 Twin Studies Allow an Estimation of Heritability in Humans......Page 709
23.5 Quantitative Trait Loci Are Useful in Studying Multifactorial Phenotypes......Page 711
GENETICS, TECHNOLOGY, AND SOCIETY: The Green Revolution Revisited: Genetic Research with Rice......Page 714
Insights and Solutions......Page 715
Problems and Discussion Questions......Page 716
24 Genetics of Behavior......Page 720
24.1 The Behavior-First Approach Can Establish Genetic Strains with Behavioral Differences......Page 722
24.2 The Gene-First Approach Analyzes Mutant Alleles to Study Mechanisms That Underlie Behavior......Page 725
24.3 Human Behavior Has Genetic Components......Page 728
CASE STUDY: Primate models for human disorders......Page 732
Summary Points......Page 733
Problems and Discussion Questions......Page 734
25 Population and Evolutionary Genetics......Page 737
25.1 Genetic Variation Is Present in Most Populations and Species......Page 738
25.2 The Hardy–Weinberg Law Describes Allele Frequencies and Genotype Frequencies in Populations......Page 740
25.3 The Hardy–Weinberg Law Can Be Applied to Human Populations......Page 742
25.4 Natural Selection Is a Major Force Driving Allele Frequency......Page 746
25.5 Mutation Creates New Alleles in a Gene Pool......Page 749
25.7 Genetic Drift Causes Random Changes in Allele Frequency in Small Populations......Page 750
25.8 Nonrandom Mating Changes Genotype Frequency but Not Allele Frequency......Page 752
25.9 Reduced Gene Flow, Selection, and Genetic Drift Can Lead to Speciation......Page 753
25.10 Phylogeny Can Be Used to Analyze Evolutionary History......Page 756
GENETICS, TECHNOLOGY, AND SOCIETY: Tracking Our Genetic Footprints out of Africa......Page 760
Insights and Solutions......Page 761
Problems and Discussion Questions......Page 762
26 Conservation Genetics......Page 765
26.1 Genetic Diversity Is the Goal of Conservation Genetics......Page 767
26.2 Population Size Has a Major Impact on Species Survival......Page 769
26.3 Genetic Effects Are More Pronounced in Small, Isolated Populations......Page 771
26.4 Genetic Erosion Threatens Species’ Survival......Page 774
26.5 Conservation of Genetic Diversity Is Essential to Species Survival......Page 775
CASE STUDY: The flip side of the green revolution......Page 778
GENETICS, TECHNOLOGY, AND SOCIETY: Gene Pools and Endangered Species: The Plight of the Florida Panther......Page 779
Problems and Discussion Questions......Page 780
Appendix A: Selected Readings......Page 783
Appendix B: Answers......Page 795
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