BIOL 3600 Lecture Notes - Lecture 11: Genetic Load, Allele Frequency, Natural Selection
Document Summary
Fisher orr genetic model: adaptation towards optima tends to involve smaller and smaller steps. Wright"s fitness landscape: p = p(wa-wavg)/wavg, directional selection, aa w=0. 9, aa: w=0. 8, aa: w=0. 2, selection coefficient (s) = 1-w, fitness (w, allele frequency trajectory, p" = p(1+s)/(1+ps) Frequency dependent selection: positive common alleles are more beneficial, negative uncommon/rare alleles are more beneficial, selection pressures can change when environments change, soft sweeps ~ involve adaptation. Genetic hitchhiking: natural selection affects amount of genetic diversity at linked loci. Implication: scans of selection can implicate adaptive genomic regions. Mutation selection balance: deleterious mutations are maintained due to balance between mutation and selection.
