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What is the frequency of A1 in the next generation?

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Presentation on theme: "What is the frequency of A1 in the next generation?"— Presentation transcript:

1 What is the frequency of A1 in the next generation?
p2w11 + pqw12 pt + 1 = p2w11 + 2pqw12 + q2w22 What is the change in frequency of A2 per generation? After some algebra Dp = pt pt = p / w (pw11 + qw12 - w ) With this equation we can substitute values for relative fitness and analyze various cases of selection.

2 Gene Action Fitness Relationship A1A1 A1A2 A2A2 1 + s 1 + s 1
Dominance A1A1 A1A2 A2A2 1 + s Recessivity A1A1 A1A2 A2A2 1 + s t Overdominance A1A1 A1A2 A2A2 1 + s t Underdominance

3 Dominance Genotype A1A1 A1A2 A2A2 Fitness 1 + s s S = 0.01 A1

4 Recessive Genotype A1A1 A1A2 A2A2 Fitness 1 + s S = 0.01 A1

5 Evolution in lab populations of flour beetles support theoretical predictions. Dawson (1970)

6 Overdominance/Heterozygote Superiority
Genotype A1A1 A1A2 A2A2 Fitness 1 + s t S = t = Stable equilibrium is reached A1 Genetic diversity is maintained

7 Viable allele did not fix in the population
Mukai and Burdick 1958

8 Underdominance Genotype A1A1 A1A2 A2A2 Fitness 1 + s t S = t = 0.02 Unstable equilibrium A1 A1 maybe fixed or lost from the population

9 Frequency-Dependent Selection
Allele frequencies in a population remain near an equilibrium because selection favors the rarer allele. As a result, both alleles are maintained in the population. Perissodus

10 12.14(2) Multiple-niche polymorphism in the black-bellied seedcracker
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11 12.12 Gene flow reduces adaptation to fish predation among larvae of a salamander
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12 12.7(1) Plots of mean fitness (v) against allele frequency (p) for one locus with two alleles
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13 12.7(2) Plots of mean fitness (v) against allele frequency (p) for one locus with two alleles
C:\Figures\Chapter12\high-res\Evolution-Fig jpg

14 12.7(3) Plots of mean fitness (v) against allele frequency (p) for one locus with two alleles
C:\Figures\Chapter12\high-res\Evolution-Fig jpg

15 12.7(4) Plots of mean fitness (v) against allele frequency (p) for one locus with two alleles
C:\Figures\Chapter12\high-res\Evolution-Fig jpg

16 12.20(1) A peak shift due to the joint action of genetic drift and natural selection
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17 12.20(2) A peak shift due to the joint action of genetic drift and natural selection
C:\Figures\Chapter12\high-res\Evolution-Fig jpg


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