Coalescence and genetic diversity in sexual populations under selection

In sexual populations, selection operates neither on the whole genome, which is repeatedly taken apart and reassembled by recombination, nor on individual alleles that are tightly linked to the chromosomal neighborhood. The resulting interference between linked alleles reduces the efficiency of sele...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2013-09, Vol.110 (39), p.15836-15841
Main Authors: Neher, Richard A., Kessinger, Taylor A., Shraiman, Boris I.
Format: Article
Language:English
Subjects:
Adaptation, Physiological - genetics
Alleles
Biological Sciences
Evolution
Evolutionary genetics
Gender
Genealogy
Genealogy and Heraldry
Genetic diversity
Genetic Fitness
Genetic loci
Genetic Loci - genetics
Genetic mutation
Genetic Variation
Genetics, Population
Genomes
Humans
Linkage Disequilibrium - genetics
Models, Genetic
Mutation - genetics
Physical Sciences
Population genetics
Quantitative genetics
Recombination, Genetic
Selection, Genetic
Simulation
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Summary:In sexual populations, selection operates neither on the whole genome, which is repeatedly taken apart and reassembled by recombination, nor on individual alleles that are tightly linked to the chromosomal neighborhood. The resulting interference between linked alleles reduces the efficiency of selection and distorts patterns of genetic diversity. Inference of evolutionary history from diversity shaped by linked selection requires an understanding of these patterns. Here, we present a simple but powerful scaling analysis identifying the unit of selection as the genomic “linkage block” with a characteristic length, [Formula], determined in a self-consistent manner by the condition that the rate of recombination within the block is comparable to the fitness differences between different alleles of the block. We find that an asexual model with the strength of selection tuned to that of the linkage block provides an excellent description of genetic diversity and the site frequency spectra compared with computer simulations. This linkage block approximation is accurate for the entire spectrum of strength of selection and is particularly powerful in scenarios with many weakly selected loci. The latter limit allows us to characterize coalescence, genetic diversity, and the speed of adaptation in the infinitesimal model of quantitative genetics.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1309697110