Hardy-Weinberg, drift, selection, quantitative genetics, QTL, GWAS, coalescent theory.
Mendelian And Population Genetics
Hardy-Weinberg equilibrium
In an infinite, randomly mating, mutation/drift/selection/migration-free population, allele frequencies stay constant and genotype…
Genetic drift
Stochastic change in allele frequency from finite-population sampling. Variance ∝ 1/(2N_e). Drives fixation/loss of alleles on timescale…
Effective population size (N_e)
Size of an ideal Wright-Fisher population with the same drift magnitude as the real population. Usually N_e ≪ census N due to sex ratio,…
Natural selection
Differential reproduction of heritable variants. Selection coefficient s = 1 − w (relative fitness); time to fixation ~ (1/s)·ln(2N_e) for…
Neutral theory of molecular evolution (Kimura)
Kimura 1968: most molecular variation is selectively neutral, fixed by drift. Substitution rate per generation = neutral mutation rate μ…
Heritability
Proportion of phenotypic variance attributable to genetic variance. Broad-sense H² = V_G/V_P; narrow-sense h² = V_A/V_P (additive only).…
Genome-wide association study (GWAS)
Hypothesis-free scan of millions of SNPs for statistical association with trait/disease across large cohorts. Multiple-testing threshold p…
Linkage disequilibrium (LD)
Non-random allelic association at linked loci. Decays with recombination over generations; used in GWAS fine-mapping and detecting…
F-statistics (Wright)
FIT, FIS, FST partition heterozygosity among total population, subpopulations, individuals. FST measures genetic differentiation; key for…
Coalescent theory
Kingman 1982: trace lineages backward in time to most-recent common ancestor. Foundation of modern population genomics inference (PSMC,…