LIFESCI 1 Lecture Notes - Lecture 7: Natural Selection 2, Allele Frequency, Genetic Drift
21 Jan 2015
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Document Summary
Evolution: the change in the frequency of alleles within a gene pool: individuals don"t evolve, populations do. Mechanisms of evolution (in addition to mutations: 1. ) Evolution by natural selection: x-axis = allele frequency; y-axis = time in generation (0-50, if a trait that is selected for, it will increase over time, example: non-poisonous king snakes mimic poisonous coral snake. Improves their survival the snake skin pattern is selected for and increases in frequency over time. Buri experiment: 107 populations of flies, 8 males + 8 females in each population, starting allele frequency = 50% 16/32 bw and 16/32 bw75, 19 generations of evolution (let them breed and then randomly pick. Genetic variation will be lower in this smaller subset of the original population: example of founder effect: subset of original population colonizes a new area. As the founder population evolves, you might end up with a very different composition from the originating population.
