BIO220H1 Lecture Notes - Lecture 3: Oomycete, Tuber, Genetic Drift
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BIO220H1 Full Course Notes
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Bio220: lecture 3: genetic diversity in agricultural systems. Domestication of crops leads to a severe bottleneck: only a subset are chosen to be cultivated. Strong artificial selection: breed and reatin the best performing crop plants. H: average frequency of heterozygous individuals per gene locus. P: proportion of gene loci that are polymorphic. Pi: average number of nucleotide differences per site, for any randomly sampled pair of nucleotides. Application of artificial selection before discovery of genetics and natural selection. What does a 43% loss of variation mean. They reduce the effective population size (ne) N= total number of adults in a population. Variation in number of progeny among indivduals. This happens even in the absence of selection. Natural or artificial selection reduces ne even further. Ne can be measured as a species average across the genome. Artificial selection lead to reduction in ne that are locus specific. 2% to 4% of the teosinte genome experienced strong artificial selection during domestication.
