For courses in Genetics found in biological sciences, agriculture, forestry, and health sciences. Essentials of Genetics presents a succinct overview of the discipline with balanced coverage of both classical and modern genetics. While emphasizing concepts and problem-solving, the authors' clear writing and up-to-date coverage of new research captures students' interest. Classic and modern experiments and applications illustrate the nature of scientific discovery, helping students connect the science of genetics to the issues of today.

Table of Contents:
Preface. 1. An Introduction to Genetics. Genetics Has a Rich and Interesting History. Nucleic Acids and Proteins Serve as the Molecular Basis of Genetics. Genetics Has Been Investigated Using Many Different Approaches. Genetics Has a Profound Impact on Society. GENETICS, TECHNOLOGY, AND SOCIETY. The Frankenfood Debates: Genetically Modified Foods. Chapter Summary. Key Terms. Problems and Discussion Questions. Selected Readings. 2. Mitosis and Meiosis. Cell Structure Is Closely Tied to Genetic Function. Chromosomes Exist in Homologous Pairs in Diploid Organisms. Mitosis Partitions Chromosomes into Dividing Cells. The Cell Cycle Is Genetically Regulated. Meiosis Reduces the Chromosome Number from Diploid to Haploid in Germ Cells and Spores. The Development of Gametes Varies During Spermatogenesis and Oogenesis. Meiosis Is Critical to the Successful Sexual Reproduction of All Diploid Organisms. Electron Microscopy Has Revealed the Cytological Nature of Mitotic and Meiotic Chromosomes. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 3. Mendelian Genetics. Mendel Used a Model Experimental Approach to Study Patterns of Inheritance. The Monohybrid Cross Reveals How One Trait Is Transmitted from Generation to Generation. Mendel's Dihybrid Cross Generated a Unique F2 Ratio. The Trihybrid Cross Demonstrates that Mendel's Principles Apply to Inheritance of Multiple Traits. Mendel's Work Was Rediscovered in the Early Twentieth Century. Independent Assortment Leads to Extensive Genetic Variation. Laws of Probability Help to Explain Genetic Events. How Mendel's Peas Become Wrinkled: A Molecular Explanation. Chi-Square Analysis Evaluates the Influence of Chance on Genetic Data. Pedigrees Reveal Patterns of Inheritance in Humans. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 4. Modification of Mendelian Ratios. Alleles Alter Phenotypes in Different Ways. Geneticists Use a Variety of Symbols for Alleles. Neither Allele Is Dominant in Incomplete, or Partial, Dominance. In Codominance, the Influence of Both Alleles in a Heterozygote Is Clearly Evident. Multiple Alleles of a Gene May Exist in a Population. Lethal Alleles Represent Essential Genes. Combinations of Two Gene Pairs with Two Modes of Inheritance Modify the 9:3:3:1 Ratio. Phenotypes Are Often Affected by More than One Gene. Complementation Analysis Can Determine if Two Mutations Causing a Similar Phenotype Are Alleles. X-Linkage Describes Genes on the X Chromosome. In Sex-Limited and Sex-Influenced Inheritance, an Individual's Sex Influences the Phenotype. Phenotypic Expression Is Not Always a Direct Reflection of the Genotype. Extranuclear Inheritance Modifies Mendelian Patterns. GENETICS, TECHNOLOGY, AND SOCIETY. Improving the Genetic Fate of Purebred Dogs. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 5. Sex Determination and Sex Chromosomes. Life Cycles Depend on Sexual Differentiation. X and Y Chromosomes Were First Linked to Sex Determination Early in the Twentieth Century. The Y Chromosome Determines Maleness in Humans. The Ratio of Males to Females in Humans Is Not 1.0. Dosage Compensation Prevents Excessive Expression of X-Linked Genes in Humans and Other Mammals. The Ratio of X Chromosomes to Sets of Autosomes Determines Sex in Drosophila. Temperature Variation Controls Sex Determination in Reptiles. GENETICS, TECHNOLOGY, AND SOCIETY. A Question of Gender: Sex Selection in Humans. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 6. Quantitative Genetics. Continuous Variation Characterizes the Inheritance of Quantitative Traits. The Study of Polygenic Traits Relies on Statistical Analysis. Heritability Is a Measure of the Genetic Contribution to Phenotypic Variability. Quantitative Trait Loci Can Be Mapped. GENETICS, TECHNOLOGY, AND SOCIETY. The Green Revolution Revisited. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 7. Chromosome Mutations: Variation in Number and Arrangement. Specific Terminology Describes Variations in Chromosome Number. Variation in the Number of Chromosomes Results from Nondisjunction. Monosomy, the Loss of a Single Chromosome, May Have Severe Phenotypic Effects. Trisomy Involves the Addition of a Chromosome to a Diploid Genome. Polyploidy, in Which More than Two Haploid Sets of Chromosomes Are Present, Is Prevalent in Plants. Variation Occurs in the Structure and Arrangement of Chromosomes. A Deletion Is a Missing Region of a Chromosome. A Duplication Is a Repeated Segment of a Chromosome. Inversions Rearrange the Linear Gene Sequence. Translocations Alter the Location of Chromosomal Segments in the Genome. Fragile Sites in Humans Are Susceptible to Chromosome Breakage. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 8. Linkage and Chromosome Mapping in Eukaryotes. Genes Linked on the Same Chromosome Segregate Together. Crossing over Serves as the Basis of Determining the Distance Between Genes During Mapping. Determining the Gene Sequence During Mapping Relies on the Analysis of Multiple Crossovers. As the Distance Between Two Genes Increases, Mapping Estimates Become More Inaccurate. Drosophila Genes Have Been Extensively Mapped. Lod Score Analysis and Somatic Cell Hybridization Were Historically Important in Creating Human Chromosome Maps. Linkage and Mapping Studies Can Be Performed in Haploid Organisms. Other Aspects of Genetic Exchange. Did Mendel Encounter Linkage? Why Didn't Gregor Mendel Find Linkage? Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 9. Mapping in Bacteria and Bacteriophages. Bacteria Mutate Spontaneously and Grow at an Exponential Rate. Conjugation Is One Means of Genetic Recombination in Bacteria. Rec Proteins Are Essential to Bacterial Recombination. F Factors Are Plasmids. Transformation Is Another Process Leading to Genetic Recombination in Bacteria. Bacteriophages Are Bacterial Viruses. Transduction Is Virus-Mediated Bacterial DNA Transfer. Bacteriophages Undergo Intergenic Recombination. GENETICS, TECHNOLOGY, AND SOCIETY. Eradicating Cholera: Edible Vaccines. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 10. DNA Structure and Analysis. The Genetic Material Must Exhibit Four Characteristics. Until 1944, Observations Favored Protein as the Genetic Material. Evidence Favoring DNA as the Genetic Material Was First Obtained During the Study of Bacteria and Bacteriophages. Indirect and Direct Evidence Supports the Concept that DNA Is the Genetic Material in Eukaryotes. RNA Serves as the Genetic Material in Some Viruses. The Structure of DNA Holds the Key to Understanding Its Function. Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid. Alternative Forms of DNA Exist. The Structure of RNA Is Chemically Similar to DNA, but Single-Stranded. Many Analytical Techniques Have Been Useful During the Investigation of DNA and RNA. Nucleic Acids Can Be Separated Using Electrophoresis. GENETICS, TECHNOLOGY, AND SOCIETY. The Twists and Turns of the Helical Revolution. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 11. DNA-Replication and Synthesis. DNA Is Reproduced by Semiconservative Replication. DNA Synthesis in Bacteria Involves Three Polymerases, as Well as Other Enzymes. Many Complex Issues Must Be Resolved During DNA Replication. A Coherent Model Summarizes DNA Replication. Replication Is Controlled by a Variety of Genes. Eukaryotic DNA Synthesis Is Similar to, but More Complex than, Synthesis in Prokaryotes. The Ends of Linear Chromosomes Are Problematic During Replication. DNA Recombination, Like DNA Replication, Is Directed by Specific Enzymes. GENETICS, TECHNOLOGY, AND SOCIETY. Telomerase: The Key to Immortality? Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 12. Chromosome Structure and DNA Sequence Organization. Viral and Bacterial Chromosomes Are Relatively Simple DNA Molecules. Mitochondria and Chloroplasts Contain DNA Similar to Bacteria and Viruses. Specialized Chromosomes Reveal Variations in the Organization of DNA. DNA Is Organized into Chromatin in Eukaryotes. Eukaryotic Genomes Demonstrate Complex Sequence Organization Characterized by Repetitive DNA. The Vast Majority of a Eukaryotic Genome Does Not Encode Functional Genes. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 13. The Genetic Code and Transcription. The Genetic Code Exhibits a Number of Characteristics. Early Studies Established the Basic Operational Patterns of the Code. Studies by Nirenberg, Matthaei, and Others Deciphered the Code. The Coding Dictionary Reveals the Function of the 64 Triplets. The Genetic Code Has Been Confirmed in Studies of Bacteriophage MS2. The Genetic Code Is Nearly Universal. Transcription Synthesizes RNA on a DNA Template. RNA Polymerase Directs RNA Synthesis. Transcription in Eukaryotes Differs from Prokaryotic Transcription in Several Ways. The Coding Regions of Eukaryotic Genes Are Interrupted by Intervening Sequences. RNA Editing Modifies the Final Transcript. GENETICS, TECHNOLOGY, AND SOCIETY. Antisense Oligonucleotides: Attacking the Messenger. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 14. Translation and Proteins. Translation of mRNA Depends on Ribosomes and Transfer RNAs. Translation of mRNA Can Be Divided into Three Steps. Crystallographic Analysis Has Revealed Many Details About the Functional Prokaryotic Ribosome. Translation Is More Complex in Eukaryotes. The Initial Insight that Proteins Are Important in Heredity Was Provided by the Study of Inborn Errors of Metabolism. Studies of Neurospora Led to the One-Gene: One-Enzyme Hypothesis. Studies of Human Hemoglobin Established that One Gene Encodes One Polypeptide. The Nucleotide Sequence of a Gene and the Amino Acid Sequence of the Corresponding Protein Exhibit Colinearity. Protein Structure Is the Basis of Biological Diversity. Posttranslational Modification Alters the Final Protein Product. Protein Function Is Directly Related to the Structure of the Molecule. Proteins Consist of Functional Domains. GENETICS, TECHNOLOGY, AND SOCIETY. Mad Cows and Heresies: The Prion Story. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 15. Gene Mutation, DNA Repair, and Transposable Elements. Mutations May Be Classified in Various Ways. Genetic Techniques, Cell Cultures, and Pedigree Analysis Are All Used to Detect Mutations. The Spontaneous Mutation Rate Varies Greatly Among Organisms. Mutations Occur in Many Forms and Arise in Different Ways. Ultraviolet and Ionizing Radiation Are Mutagenic. Gene Sequencing Has Enhanced Understanding of Mutations in Humans. The Ames Test Is Used to Assess the Mutagenicity of Compounds. Organisms Can Counteract DNA Damage by Activating Several Types of Repair Systems. Site-Directed Mutagenesis Allows Researchers to Investigate Specific Genes. Transposable Genetic Elements Move Within the Genome and May Disrupt Genetic Function. GENETICS, TECHNOLOGY, AND SOCIETY. Chernobyl's Legacy. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 16. Regulation of Gene Expression. Prokaryotes Exhibit Efficient Genetic Mechanisms to Respond to Environmental Conditions. Lactose Metabolism in E. coli Is Regulated by an Inducible System. Crystal Structure Analysis of Repressor Complexes Has Confirmed the Operon Model. Tryptophan Metabolism in E. coli Is Controlled by a Repressible Gene System. Eukaryotic Gene Regulation Differs from Regulation in Prokaryotes. Regulatory Elements and Transcription Factors Control the Expression of Eukaryotic Genes. Steroid Hormones Regulate Some Genes. Posttranscriptional Events Also Regulate Gene Expression. GENETICS, TECHNOLOGY, AND SOCIETY. Why Is There No Effective AIDS Vaccine? Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 17. Recombinant DNA Technology. An Overview of Recombinant DNA Technology. Recombinant DNA Molecules Are Constructed Using Several Components. Cloning in Prokaryotic Host Cells. Cloning in Eukaryotic Host Cells. The Polymerase Chain Reaction Permits Cloning Without Host Cells. Libraries Are Collections of Cloned Sequences. Specific Clones Can Be Recovered from a Library. Cloned Sequences Can Be Characterized in Several Ways. DNA Sequencing: The Ultimate Way to Characterize a Clone. GENETICS, TECHNOLOGY, AND SOCIETY. Beyond Dolly: The Cloning of Humans. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 18. Genomics, Bioinformatics, and Proteomics. Genomics: Sequencing Helps Identify and Map All Genes in a Genome. Bioinformatics Provides Tools for Analyzing Genomic Information. Functional Genomics Classifies Genes and Identifies Their Functions. Prokaryotic Genomes Have Some Unexpected Features. Eukaryotic Genomes Have a Mosaic of Organizational Patterns. Genomics Provides Insight into Genome Evolution. Comparative Genomics: Multigene Families Diversify Gene Function. Proteomics Identifies and Analyzes the Proteins in a Cell. GENETICS, TECHNOLOGY, AND SOCIETY. Footprints of a Killer. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 19. Applications and Ethics of Biotechnology. Biotechnology Has Revolutionized Agriculture. Pharmaceutical Products Are Synthesized in Genetically Altered Organisms. Biotechnology Is Used to Diagnose and Screen Genetic Disorders. Genetic Disorders Can Be Treated by Gene Therapy. Gene Therapy Raises Many Ethical Concerns. Ethical Issues Are an Outgrowth of the Human Genome Project. Mapping Human Genes with Recombinant DNA Technology. DNA Fingerprints Can Identify Individuals. GENETICS, TECHNOLOGY, AND SOCIETY. Gene Therapy-Two Steps Forward or Two Steps Back? Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 20. Genes and Development. Basic Concepts in Developmental Genetics. Maternal and Zygotic Genes Interact to Establish the Body Axis in Drosophila. Homeotic Genes Control Pattern Formation Along the Anterior-Posterior Body Axis. Cell-Cell Interactions Can Control Developmental Fate. GENETICS, TECHNOLOGY, AND SOCIETY. Stem Cell Wars. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 21. The Genetic Basis of Cancer. Cancer as a Disorder of the Cell Cycle. Genes that Control the Cell Cycle Are Involved in Cancer. Tumor-Suppressor Genes Repress Cell Division. Proto-oncogenes Promote or Maintain Cell Division. Colon Cancer as a Genetic Model of Cancer. The Pathway to Cancer Leads Through Gatekeeper and Caretaker Genes. Chromosomal Translocations Are a Hallmark of Leukemia. Environmental Factors Contribute to Cancer. GENETICS, TECHNOLOGY, AND SOCIETY. The Double-Edged Sword of Genetic Testing: The Case of Breast Cancer. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 22. Population Genetics. Populations and Gene Pools. Calculating Allele Frequencies. The Hardy-Weinberg Law. Extensions of the Hardy-Weinberg Law. Using the Hardy-Weinberg Law: Calculating Heterozygote Frequency. Natural Selection. Mutation. Migration. Genetic Drift. Nonrandom Mating. GENETICS, TECHNOLOGY, AND SOCIETY. Tracking Our Genetic Footprints out of Africa. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 23. Genetics and Evolution. Speciation Can Occur by Transformation or Splitting of Gene Pools. Genetic Variation Is Present in Populations and Species. Explaining High Levels of Genetic Variation in Populations. The Genetic Structure of Populations Changes Across Space and Time. Reduced Gene Flow, Selection, and Drift Can Form New Species. Using Genetic Differences to Reconstruct Evolutionary History. Evolutionary History Can Be Used to Answer Many Questions. GENETICS, TECHNOLOGY, AND SOCIETY. What Can We Learn from the Failure of the Eugenics Movement? Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. 24. Conservation Genetics. Genetic Diversity Is at the Heart of Conservation Genetics. Population Size Has a Major Impact on Species Survival. Genetic Effects Are More Pronounced in Small, Isolated Populations. Genetic Erosion Diminishes Genetic Diversity. Conservation of Genetic Diversity Is Essential to Species Survival. GENETICS, TECHNOLOGY, AND SOCIETY. Gene Pools and Endangered Species: The Plight of the Florida Panther. Chapter Summary. Key Terms. Insights and Solutions. Problems and Discussion Questions. Selected Readings. Appendix: Answers to Selected Problems. Glossary. Index.