Introduction 1
About This Book 1
Conventions Used in This Book 2
Foolish Assumptions 2
How This Book is Organized 3
Part 1: The Lowdown on Genetics: Just the Basics 3
Part 2: DNA: The Genetic Material 3
Part 3: Genetics and Your Health 3
Part 4: Genetics and Your World 3
Part 5: The Part of Tens 4
Icons Used in This Book 4
Beyond This Book 4
Where to Go from Here 5
Part 1: The Lowdown on Genetics: Just the Basics 7
Chapter 1: Welcome to Genetics: What's What and Who's Who 9
What is Genetics? 9
Classical genetics: Transmitting traits from generation to generation 10
Molecular genetics: DNA and the chemistry of genes 11
Population genetics: Genetics of groups 12
Quantitative genetics: Getting a handle on heredity 13
Genetics as a Career 13
Exploring a genetics lab 14
Sorting through jobs in genetics 15
Chapter 2: Basic Cell Biology 21
Looking Around Your Cell 22
Cells without a nucleus 22
Cells with a nucleus 23
What's in a nucleus? 25
Examining the basics of chromosomes 25
So Where Are My Genes? 27
Mitosis: Splitting Up 29
Step 1: Time to grow 30
Step 2: Divvying up the chromosomes 31
Step 3: The big divide 33
Meiosis: Making Cells for Reproduction 34
Meiosis I 35
Meiosis II 37
Mommy, where did I come from? 38
Chapter 3: Visualize Peas: Discovering the Laws of Inheritance 41
Gardening with Gregor Mendel 42
Speaking the Language of Inheritance 44
Simplifying Inheritance 45
Establishing dominance 45
Segregating alleles 47
Declaring independence 48
Finding Unknown Alleles 50
Applying Basic Probability to the Likelihood of Inheritance 50
Solving Simple Genetics Problems 52
Deciphering a monohybrid cross 53
Tackling a dihybrid cross 53
Chapter 4: Law Enforcement: Mendel's Laws Applied to Complex Traits 57
Dominant Alleles Rule Sometimes 58
Wimping out with incomplete dominance 58
Keeping it fair with codominance 59
Dawdling with incomplete penetrance 60
Alleles Causing Complications 61
More than two alleles 61
Lethal alleles 63
Making Life More Complicated 63
When genes interact 63
Genes in hiding 65
Genes linked together 66
One gene with many phenotypes 69
Uncovering More Exceptions to Mendel's Laws 70
Epigenetics 70
Genomic imprinting 70
Anticipation 71
Environmental effects 72
Part 2: DNA: The Genetic Material 73
Chapter 5: DNA: The Basis of Life 75
Chemical Ingredients of DNA 76
Covering the bases 76
Adding a spoonful of sugar and a little phosphate 78
Assembling the Double Helix: The Structure of DNA 79
Starting with one: Weaving a single strand 79
Doubling up: Adding the second strand 81
Examining Different Varieties of DNA 85
Nuclear DNA 85
Mitochondrial DNA 85
Chloroplast DNA 86
Digging into the History of DNA 87
Discovering DNA 87
Obeying Chargaff's rules 88
Hard feelings and the helix: Franklin, Wilkins, Watson, and Crick 88
Chapter 6: Chromosomes: The Big Picture 91
Deconstructing the Double Helix 92
Anatomy of a Chromosome 93
Two Chromosomes Are Better than One (or Three) 95
Sex Chromosomes: Is It a Boy or Girl? 96
Sex determination in humans 97
Sex determination in other organisms 101
Chapter 7: Replication: A Copy Machine for DNA 105
Unzipped: Creating the Pattern for More DNA 106
How DNA Copies Itself 109
Meeting the replication crew 110
Splitting the helix 113
Priming the pump 115
Leading and lagging 115
Joining all the pieces 117
Proofreading replication 117
Replication in Eukaryotes 118
Pulling up short: Telomeres 118
Finishing the job 120
How Circular DNAs Replicate 120
Theta 121
Rolling circle 121
D-loop 122
Chapter 8: DNA Sequencing: Decoding the Genome 123
Sequencing: Reading the Language of DNA 124
Identifying the players in DNA sequencing 124
Finding the message in sequencing results 127
Newer, cheaper, faster 127
Sequencing Your Way to the Human Genome 129
The Human Genome Project 130
Trying on a Few Genomes 132
The yeast genome 134
The elegant roundworm genome 134
The chicken genome 135
Chapter 9: RNA: DNA's Close Cousin 137
You Already Know a Lot about RNA 137
Using a slightly different sugar 138
Meeting a new base: Uracil 139
Stranded! 140
Transcription: Copying DNA's Message into RNA's Language 141
Getting ready to transcribe 142
Initiation 146
Elongation 147
Termination 147
Post-transcription Processing 148
Adding cap and tail 148
Editing the message 149
Chapter 10: Translating the Genetic Code 151
Discovering the Good in a Degenerate 152
Considering the combinations 153
Framed! Reading the code 154
Not quite universal 155
Meeting the Translating Team 155
Taking the Translation Trip 156
Initiation 156
Elongation 159
Termination 160
Proteins Are Precious Polypeptides 162
Recognizing radical groups 162
Giving the protein its shape 162
Chapter 11: Gene Expression: What a Cute Pair of Genes 165
Getting Your Genes Under Control 166
To Be Expressed or Not To Be Expressed? 166
Regulating Gene Expression: A Time and Place for Everything 168
Controlling Transcription Before It Starts 169
Regulation of Gene Transcription: Flipping the Switch 170
Sequences controlling genes 170
Proteins controlling transcription 172
Hormones controlling transcription 173
Retroactive Control: Things That Happen after Transcription 174
Nip and tuck: RNA splicing 175
Shut up! mRNA silencing 175
mRNA expiration dates 177
Gene Control Lost in Translation 177
Modifying where translation occurs 177
Modifying when translation occurs 178
Modifying the protein shape 179
Prokaryotic Gene Expression 179
Bacterial gene organization 179
Bacterial gene expression 180
Part 3: Genetics and Your Health 181
Chapter 12: When Things Go Wrong: Changes in DNA Sequence 183
Heritable or Not Heritable? 184
Facing the Consequences of Sequence Variants 184
Sorting Out Terminology 185
The phenotypic effect of a DNA sequence change 185
The type of DNA sequence change 186
What Causes Sequence Variants? 189
Spontaneous sequence variants 190
Induced sequence variants 194
Evaluating Options for DNA Repair 198
Chapter 13: Chromosome Disorders: It's All a Numbers Game 199
Chromosome Numbers: No More and No Less 200
Aneuploidy: Extra or missing chromosomes 200
Aneuploidy of the Autosomal Chromosomes 202
When chromosomes go missing 202
When too many chromosomes are left in 202
Aneuploidy of the Sex Chromosomes 205
Extra Xs 205
Extra Ys 206
Monosomy X 206
Exploring Variations in Chromosome Structure 206
Duplications 207
Deletions 208
Inversions 208
Translocations 209
Reciprocal translocations 209
Robertsonian translocations 210
Other things that go awry with chromosomes 211
How Chromosomes Are Studied 212
Big enough to see 212
Too small for the naked eye 214
Non-Invasive Prenatal Testing for Aneuploidy 215
Chapter 14: Taking a Closer Look at the Genetics of Cancer 217
Defining Cancer 218
Benign growths: Not always so harmless 218
Malignancies: Seriously scary results 219
Metastasis: Cancer on the move 220
Recognizing Cancer as a DNA Disease 221
Exploring the cell cycle and cancer 222
Demystifying chromosome abnormalities 228
Breaking Down the Types of Cancers 229
Hereditary Breast Cancer 231
Hereditary colorectal cancer 232
Chapter 15: Genetic Counseling, Risk Assessment, and Genetic Testing 235
Getting to Know Genetic Counselors 236
Building and Analyzing a Family Tree 237
Autosomal Inheritance: No Differences Among the Sexes 240
Autosomal dominant traits and disorders 240
Autosomal recessive traits and disorders 241
Found on Sex Chromosomes: Sex-linked Inheritance 244
X-linked recessive traits 245
X-linked dominant traits 247
Y-linked traits 248
Sex-limited traits 249
Sex-influenced traits 249
Testing for Genetic Disorders 249
Diagnostic testing 251
Prenatal diagnosis 251
Carrier testing 252
Predictive and susceptibility testing 252
Preimplantation genetic diagnosis 253
Pharmacogenetic testing 254
Chapter 16: Treating Genetic Disorders and Using Genetics to Tailor Treatment 255
Alleviating Genetic Disease through Gene Therapy 256
Inserting Healthy Genes into the Picture 256
Finding Vehicles to Get Genes to Work 259
Viruses that join right in 260
Viruses that are a little standoffish 261
Progress on the Gene Therapy Front 261
Utilizing Genetic Information for Precision Medicine 263
Pharmacogenetics (and pharmacogenomics) 263
Cytochrome P450 and drug metabolism 264
Decreasing the risk of side effects of treatment 266
Increasing the effectiveness of treatment 266
Part 4: Genetics and Your World 269
Chapter 17: Tracing Human History and the Future of the Planet 271
Genetic Variation is Everywhere 272
Allele frequencies 272
Genotype frequencies 274
Breaking Down the Hardy-Weinberg Law of Population Genetics 275
Relating alleles to genotypes 275
Violating the law 277
Mapping the Gene Pool 279
One big happy family 279
Ancestry testing 280
Uncovering the secret social lives of animals 281
Changing Forms over Time: The Genetics of Evolution 282
Genetic variation is key 283
Where new species come from 283
Growing the evolutionary tree 284
Chapter 18: Solving Mysteries Using DNA 287
Rooting through Your DNA to Find Your Identity 288
Investigating the Scene: Where's the DNA? 290
Collecting biological evidence 290
Moving to the lab 292
Employing DNA to Catch Criminals (And Free the Innocent) 297
Matching the evidence to the bad guy 297
Taking a second look at guilty verdicts 299
It's All Relative: Finding Family 300
Paternity testing 300
Relatedness testing 302
Chapter 19: Genetic Makeovers: Using Genetic Engineering to Change the Genome 307
Genetically Modified Organisms Are Everywhere 308
Old Genes in New Places 309
Following the transgenesis process 311
Making a transgene using recombinant DNA technology 311
Modifying the gene to reside in its new home 313
Looking at the GMO Menagerie 313
Transgenic animals 313
Transgenic insects 316
Transgenic bacteria 316
Transgenic plants 318
Getting new genes into the plant 318
Exploring commercial applications 319
Weighing points of contention 320
Changing the Blueprint: Gene Editing 321
CRISPR-Cas9 gene editing 323
Germline versus somatic gene editing 325
Discussing the ethics of gene editing 325
Chapter 20: Giving Ethical Considerations Their Due 327
Profiling Genetic Discrimination 327
Ordering Up Designer Babies 329
Ethical Issues Surrounding Genetic Testing 330
Informed Consent 331
Patient Autonomy 333
Privacy and Confidentiality 334
Incidental Findings 335
Direct-to-Consumer Testing 336
Practicing Safe Genetic Treatments 337
Genetic Property Rights 338
Part 5: The Part of Tens 339
Chapter 21: Ten Defining Events in Genetics 341
The Publication of Darwin's The Origin of Species 341
The Rediscovery of Mendel's Work 342
DNA Transformation 343
The Discovery of Jumping Genes 344
The Birth of DNA Sequencing 345
The Invention of PCR 345
The Development of Recombinant DNA Technology 346
The Invention of DNA Fingerprinting 347
The Birth of Developmental Genetics 347
The Work of Francis Collins and the Human Genome Project 348
Chapter 22: Ten Hot Issues in Genetics 349
Direct-to-Consumer Genetic Testing 349
Whole Exome Sequencing 350
Whole Genome Sequencing 352
Stem Cell Research 352
The ENCODE Project 353
Proteomics 354
Gene Chips 355
Evolution of Antibiotic Resistance 356
Circumventing Mother Nature 356
Genetics from Afar 357
Glossary 359
Index 365
