GENE20001 Lecture Notes - Lecture 33: Allele, Genetic Drift
Document Summary
Assortative mating: individuals of a genotype mate more/less frequently with individuals of a given genotype than expected from their respective frequencies. Positive assortative mating: choose to mate with individuals with similar genotypes. Negative assortative mating: choose t mate with individuals with different genotypes. Inbreeding: higher frequency of matings between relatives than expected for randomness. Inbreeding coefficient, f: the probability an individual receives at a given locus, two alleles that are identical by descent. Pedigrees show when genes are identical by descent. Inbreeding of humans have very small f but different. Allele frequencies do not change if inbreeding acts in isolation. 0. 456 = 0. 62 + 2 x 0. 6 x 0. 4 x f. solve. Consistent inbreeding leads to a cumulative increase in f. Note aa decreases, aa and aa increase, f increases, qa remains constant. Inbreeding can occur in large populations but often in small populations. May occur in parallel with genetic drift (e. g. amish of lancaster county, pennsylvania)
