BIO120H1 Lecture Notes - Lecture 7: Zygosity, Eichhornia Crassipes, Mating System
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BIO120H1 Full Course Notes
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Lecture 7: population structure, gene flow, & genetic drift. Flight becomes maladaptive or neutral: no predators no use of flight, wings become detrimental, no selection pressure to maintain wings. The fisher-wright debate: wright: important role for population structure and genetic drift. Fisher: most evolution occurred in large populations by natural selection. Effects of selection, gene flow, and genetic drift on population divergence. Two forces pushing populations apart: gene flow bringing them together, offspring are hybrid of both species. Individuals are mating and differences are stopped from being exaggerated. How do we measure gene flow: difficulties in, observing and measuring, distinguishing potential vs. actual, distinguishing gamete vs. individual, use of, experimental approaches, neutral genetic markers. Two populations fixed for alternative alleles: allow two populations fixed for alternate alleles at a polymorphic locus, one has a fast migrating allele, one has a slow migrating allele. If it results in heterozygosity, gene flow is occurring.
