ANTH 120 Lecture Notes - Lecture 9: Allele Frequency, Genetic Drift, Gene Flow
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Anth 120 notes // spring semester 2020 // prof: andrew du, ph. d. Outline: hardy-weinberg equilibrium model as a baseline for detecting evolution. Four forces/mechanisms of evolution: mutation, geneflow, genetic drift, natural selection. Evolution: a change in allele frequencies within a population from generation to generation. Input numbers -> output expectations: compare model expectations to actual observations, ex: expectation = no change, compare to evolutionary changes, hardy-weinberg: sse simplified model to get expected allele frequencies in population"s next generation under no evolution. Hardy-weinberg equilibrium model: equilibrium - system is stable, balanced, and unchanging, hwe describes expected allele/genotype frequencies in population"s next generation, no evolution is happening, therefore there is equilibrium, what is expected in a balanced and unchanging system . If the frequency of a populations alleles do not change over time, they are in equilibrium. If observed allele frequencies don"t match model expectations, evolution is happening! Imagine a diploid population with two alleles: a & a.
