BIOL 1000 Lecture Notes - Lecture 47: Genetic Drift, Gene Flow, Natural Selection
13 May 2017
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Document Summary
Genetic drift has a significant effect on a population when there is a bottleneck effect and a founder effect. Bottleneck effect = drastic reduction in population size leaving a small surviving population that is unlikely to have the same genetic makeup as the original. Genetic drift may continue for many generations after until population is large enough again for by chance fluctuations to have less of an impact. Even if population recovers in size, may still suffer from low levels of genetic variation . Human actions can create severe bottlenecks for other species (endangered) Founder effect = a few individuals colonize an island or other new habitat. Smaller the group, the less likely the genetic makeup will represent the gene pool of the larger population they left. Gene flow = a population may gain/lose alleles when fertile individuals move into or out of a population, or when gametes are transferred between populations.
