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+ | ====Haldane 1937==== | ||
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Haldane, J. B. S. (1937). The effect of variation of fitness. //The American Naturalist//, | Haldane, J. B. S. (1937). The effect of variation of fitness. //The American Naturalist//, | ||
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Takeaway: Haldane considers the effects of deleterious mutations. Estimates are given for mutation-selection equilibrium allele frequencies and average reduction of fitness in the population. Fitness reduction is only a function of, and proportional to, mutation rates. The average individual in a population has a fitness that is a small fraction of the maximum theoretically possible if the genome were free of deleterious mutations. | Takeaway: Haldane considers the effects of deleterious mutations. Estimates are given for mutation-selection equilibrium allele frequencies and average reduction of fitness in the population. Fitness reduction is only a function of, and proportional to, mutation rates. The average individual in a population has a fitness that is a small fraction of the maximum theoretically possible if the genome were free of deleterious mutations. | ||
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===Notes=== | ===Notes=== | ||
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- | Mutated copies are removed by selection each generation ($1-f$ survive). | + | Mutated copies are removed by selection each generation ($f$ survive). |
$$N x (1-f) $$ | $$N x (1-f) $$ | ||
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==Multiple Loci== | ==Multiple Loci== | ||
- | Assuming mutations are independent both in occurrence and in fitness effects the average individual in the population has an expected fitness of | + | Pages 345--346 describe the predictions over all loci in the genome. |
$$F = \prod_i (1-m_i)$$ | $$F = \prod_i (1-m_i)$$ | ||
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where $m$ is the mutation rate $\mu$ at the $i$< | where $m$ is the mutation rate $\mu$ at the $i$< | ||
- | If the per nucleotide per generation mutation rate is $10^{-8}$ | + | If the per nucleotide per generation mutation rate is $10^{-8}$, a tenth of our 3.3 billion base pair genome is under purifying selection, and the majority of mutations are recessive in fitness effects |
- | $$F \approx (1-10^{-8})^{3.3 \times 10^8}\approx 0.037 $$ | + | $$F \approx (1-10^{-8})^{3.3 \times 10^8}\approx 0.037\mbox{.}$$ |
Therefore, our fitness is predicted to be a small fraction, approximately 3--4%, of its theoretical maximum without mutations (both new mutations that have occurred in our own genomes and mutations that we have inherited from our ancestors). | Therefore, our fitness is predicted to be a small fraction, approximately 3--4%, of its theoretical maximum without mutations (both new mutations that have occurred in our own genomes and mutations that we have inherited from our ancestors). | ||
==Other things== | ==Other things== | ||
- | Haldane discusses the effects of inbreeding and sex-linkage on these prediction and goes through quite a bit of detail | + | Haldane discusses the effects of inbreeding and sex-linkage on these prediction and goes through quite a bit of additional logical details |