OUTLINE OF GENETICS
1 Introduction 1 11 Why is genetics relevant for me? 4 2 Nature, nurture, and heritability 7 21 Phenotype, genotype and environment 7 22 Innateness, a slippery and complex concept 9 23 Some basic notions of statistics 12 231 Mean, variance and standard deviation 14 232 The normal distribution 15 233 Statistical populations and samples 19 234 Covariance and correlation 21 235 Regression 24 24 Basic notions of quantitative genetics 30 241 Partitioning the phenotype and broad-sense heritability, H2 31 242 Partitioning the genotype and narrow-sense heritability, h2 32 243 Partitioning the environment 33 244 Estimating heritability 34 245 Heritability: what it does and does not mean 37 246 The heritability of language and speech 39 247 Relationships between genotype and environment 40 248 Sharing genes between phenotypes: genetic correlations and “generalist genes” 42 3 The molecular bases of genetics 44 31 We are composed of cells 45 32 The molecules of life 48 vii 33 The genetic material 49 34 DNA: storing and transmitting information 50 35 Chromosomes are DNA molecules 53 36 Genetic loci and recombination 58 37 What is a gene? 59 371 Decoding genes: transcription and translation 61 372 Genes have structure: introns and exons 68 4 Effects of genes on phenotype 72 41 Dominance and recessiveness 72 42 Autosomal dominance and recessiveness 75 421 A dominant speech and language disorder 75 422 Recessive hearing loss 80 43 Sex-linked dominance and recessiveness 83 431 X chromosome inactivation 84 432 Anomalous colour perception 84 433 Variation in colour perception and language 88 5 Linkage disequilibrium and its role in finding genes 90 51 What is linkage disequilibrium? 90 52 Using linkage disequilibrium 93 53 Association studies 94 531 Statistical concepts: power, multiple testing correction and effect size 97 532 Controlling for other factors using regression 110 533 Accounting for population stratification 113 534 Replication as the gold standard 115 535 Combining multiple markers 116 536 The Transmission Disequilibrium Test 118 537 Examples of association studies for language and speech 120 54 Linkage studies 124 6 What do genes actually do? 131 61 Structural proteins: TECTA in the inner ear 131 62 Energy production: mitochondrial gene MTRNR1 133 63 The transportation system: MYO15A 134 64 Unexpected processes: stuttering and the lysosome 135 65 Guiding axons: ROBO1 in dyslexia and normal variation 137 66 Brain growth and development: ASPM and MCHP1 139 67 Regulating the expression of other genes: FOXP2 142 68 Neural development and neural impulse conduction: CNTNAP2 149 69 Post-transcriptional gene regulation: microRNAs 151 691 microRNAs and FOXP2 151 692 miR-96 and hearing loss 152 7 The way forward: exome and genome sequencing 153 71 Exome and genome sequencing 153 72 The “missing heritability” and the genetic architecture of complex traits 155 8 Population and evolutionary genetics 160 81 Foundations of population genetics: loci, alleles, individuals and populations 161 82 A useful baseline: the Hardy-Weinberg equilibrium 162 83 Genetic drift: the power of chance 164 84 Mutation: the creator of diversity 168 85 Selection: when differences do matter 170 851 Positive, stabilizing and disruptive selection 171 852 Hiking the fitness landscape 173 853 When selection seemingly fails 175 854 What is selected: de-focusing the individual 177 855 The (nearly) neutral theory of evolution 178 856 Detecting selection from genetic data 179 857 The evolutionary tale of FOXP2 185 86 Population structure: love is not blind 187 861 Inbreeding: mating among genetic relatives 187 862 (Dis-)assortative mating: choosing partners (un)like yourself 188 863 Structured populations: choosing the partners you can actually choose 188 864 The genetic structure of modern humans 190 87 Recent and ongoing evolution in humans 195 871 Skin colour 195 872 Hair, sweat and ear wax 196 873 Living at high altitude 197 874 Is culture shielding or selecting us? 198 9 Interactions between genetic and cultural evolution 199 91 Fighting pathogens 200 92 Eating well 202 93 Creating new languages 204 94 Genetically biased cultural evolution 207 941 Genetic biases in language 209 10 Conclusions, topics not covered, future directions 212 101 Resources for further study 213