BIO120H1 Lecture Notes - Lecture 7: Pollination, Epistasis, Mutation
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BIO120H1 Full Course Notes
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Lecture 7: population structure, gene flow, genetic drift. Wright saw an important role for population structure and genetic drift in evolution. Fisher disagreed and argued that most evolution occurred in large populations by natural selection. Population: a group of individuals of a single species occupying a given area at the same time. Migration: the movement of individuals from one population to another. Gene flow: the movement of genes from one population to another. Escape of transgenes into wild relatives by gene flow. Many crops have close relatives with which they are inter-fertile: rice, oats, canola, carrots. **most gene flow occurs over a short distance but a small amount occurs as far as 1km. Risk assessment: proximity of wild relatives, pollination system wind vs. animal, mating system selfer vs. outcrosser. High risk: wind pollinated outcrosser with relatives nearby. Low risk: selfer with no relatives nearby. Stochastic (random) evolutionary forces: mutation, recombination, gene flow, genetic drift. Deterministic (non-random) evolutionary force: natural selection.
