BIO220H1 Lecture Notes - Lecture 17: Chickpea, Date Palm, Vitis Vinifera

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The world has 50,000 edible plants : yet 3 species account for 60% of food energy intake by humans! Rice, maize, wheat: typically, few genotypes are grown or harvested, despite this, abundant genetic variation exists in the wild ancestors of food crops. Severe bottleneck: only a tiny subset of individuals of the wild population are chosen to be cultivated. Consequences of domestication: reduced genetic variation, ways to measure. H: average frequency of heterozygous individuals per gene locus. P: proportion of gene loci that are polymorphic. : average number of nucleotide differences per site, for any randomly sampled pair of nucleotides. Why do we care about genetic variation in crops: clues to past artificial selection. On what traits did our ancestors select: pest and pathogen management. Can we reduce crop loss to pests: future improvement of crops. Case study: domestication of maize from teosinte: domestication 10,000 5,000 ya, application of artificial selection before discovery of genetics & natural selection.