Fitness individuals genetic contribution to the next

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Fitness individuals genetic contribution to
the next generation (zygote?zygote)
differential survival and/or reproduction
absolute fitness, Wij offspring, lifespan,
etc relative fitness, wij contribution
relative to other genotypes selection
differential, sij strength of
selection against a genotype
A1A1 A1A2 A2A2 Pr(escape) Wij
80 60 20 wij
1.0 0.75 0.25 sij
0 0.25 0.75
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How does selection change genotype and allele
frequencies?
A1A1 A1A2 A2A2 geno. freq. p2 2pq q2
relative fitness, wij w11 w12 w22 geno.
freq. p2w11 2pqw12 q2w22 after selection
w w w
average relative fitness, w p2w11 2pqw12
q2w22
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Patterns of selection
A1A1 A1A2 A2A2 w11 w12
w22 deleterious recessive 1 1
1-s recessive lethal 1 1
0 deleterious dominant 1 1
1s deleterious dominant 1 1-s
1-s deleterious intermediate 1 1-hs
1-s deleterious recessive 1 1s
1s heterozygote advantage 1-s 1
1-t heteroz. disadvantage 1s 1 1t
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change in the frequency of a deleterious
recessive
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(Roughgarden 1979)
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selection against a deleterious recessive allele
Dq
q
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change in the frequency of a deleterious dominant
(Roughgarden 1979)
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Selection against a dominant allele
Dq
q
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heterozygote advantage
Dq
q
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heterozygote disadvantage