When does frequency-independent selection maintain genetic variation?
| Autor: | Sebastian Novak, Nicholas H. Barton |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0106 biological sciences
0301 basic medicine Linkage disequilibrium Population Context (language use) Haploidy Investigations Biology 010603 evolutionary biology 01 natural sciences Linkage Disequilibrium 03 medical and health sciences Gene Frequency Genetic variation Genetics Selection Genetic Stabilizing selection education Selection (genetic algorithm) Recombination Genetic education.field_of_study 576 Genetics and evolution Models Genetic Genetic Variation Epistasis Genetic Genetic hitchhiking 030104 developmental biology Epistasis |
| Popis: | Frequency-independent selection is generally considered as a force that acts to reduce the genetic variation in evolving populations, yet rigorous arguments for this idea are scarce. When selection fluctuates in time, it is unclear whether frequency-independent selection may maintain genetic polymorphism without invoking additional mechanisms. We show that constant frequency-independent selection with arbitrary epistasis on a well-mixed haploid population eliminates genetic variation if we assume linkage equilibrium between alleles. To this end, we introduce the notion of frequency-independent selection at the level of alleles, which is sufficient to prove our claim and contains the notion of frequency-independent selection on haploids. When selection and recombination are weak but of the same order, there may be strong linkage disequilibrium; numerical calculations show that stable equilibria are highly unlikely. Using the example of a diallelic two-locus model, we then demonstrate that frequency-independent selection that fluctuates in time can maintain stable polymorphism if linkage disequilibrium changes its sign periodically. We put our findings in the context of results from the existing literature and point out those scenarios in which the possible role of frequency-independent selection in maintaining genetic variation remains unclear. |
| Databáze: | OpenAIRE |
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