Biology 1001A Lecture Notes - Lecture 13: Founder Effect, Genetic Drift, Assortative Mating
31 Oct 2016
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Document Summary
Not all genotypes have the same tness. If they don"t have the same tness, selection is happening. Absolute and relative tness: average # of surviving offspring for each genotype is de ned as its absolute. Ex: what is w (aa)? (the relative tness of genotype aa?) answer: 0. 6, by 12/20. W(aa) < w (aa) > w(aa) describes heterozygote advantage. Heterozygote disadvantage: w(rr) = w(ss) > w(rs) Which ever allele that started in higher frequency will eventually increase and reach a frequency of 1. The one that started off lower, will eventually reach 0. Heterozygote disadvantage causes rare alleles to become rarer and rarer (opposite. Monday, october 31, 2016 effect as heterozygotes advantage) Heterozygotes advantage maintains both alleles forever (until environment changes) Common alleles tend to be found in homozygotes (higher concentration) Rare alleles tend to be found in heterozygotes (bc they"re rare) In heterozygote advantage, rare alleles (found in heterozygotes) tend to increase in frequency, and common alleles decrease.
