Biology 1001A Lecture Notes - Lecture 13: Genetic Drift, Assortative Mating, Heterozygote Advantage
3 Nov 2016
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Cycle 6 lecture 13 selection, drift, and other disruptions of hardy-weinberg equilibrium. Selection happens every time not all the genotypes have the same fitness. Absolute fitness: average number of surviving offspring for each genotype (shown as. Divide by absolute fitness of most successful; genotype to calculate relative fitness (shown as w) Heterozygote advantage maintains genetic diversity (heterozygote disadvantage: wrr = wss > wrs) (heterozygote disadvantage) which ever allele is common become more and more rare, which ever allele is rare become increasingly more common. Rare alleles are mostly found in heater zygotes and common alleles are found in homozygous alleles (this determines the effect of heterozygote advantage and disadvantage) Fitness of an allele can depend in its relative abundance. Nonrandom mating perturbs hwe, but doesn t cause allele frequency to change and therefore does not cause evolution. Genetic drift is always happening when the population is less than infinite.
