Polygenic dynamics underlying the response of quantitative traits to directional selection

Götsch, Hannah; Bürger, Reinhard

doi:10.1016/j.tpb.2024.04.006

Cited by 2 publications

(1 citation statement)

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“…As a consequence, it is also difficult to link phenotype changes under selection with changes in the underlying genomic architecture. Recent progress has been made through extensive multi–locus simulations [ 8 , 9 ] or new analytical developments [ 10 – 15 ]. In particular, Hayward and Sella [ 13 ] obtained approximations that jointly characterised the phenotypic changes through time and the allele dynamics at loci contributing to trait variance.…”

Section: Introductionmentioning

confidence: 99%

Polygenic selection to a changing optimum under self–fertilisation

Hartfield,

Glémin

2024

PLoS Genet

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Many traits are polygenic, affected by multiple genetic variants throughout the genome. Selection acting on these traits involves co–ordinated allele–frequency changes at these underlying variants, and this process has been extensively studied in random–mating populations. Yet many species self–fertilise to some degree, which incurs changes to genetic diversity, recombination and genome segregation. These factors cumulatively influence how polygenic selection is realised in nature. Here, we use analytical modelling and stochastic simulations to investigate to what extent self–fertilisation affects polygenic adaptation to a new environment. Our analytical solutions show that while selfing can increase adaptation to an optimum, it incurs linkage disequilibrium that can slow down the initial spread of favoured mutations due to selection interference, and favours the fixation of alleles with opposing trait effects. Simulations show that while selection interference is present, high levels of selfing (at least 90%) aids adaptation to a new optimum, showing a higher long–term fitness. If mutations are pleiotropic then only a few major–effect variants fix along with many neutral hitchhikers, with a transient increase in linkage disequilibrium. These results show potential advantages to self–fertilisation when adapting to a new environment, and how the mating system affects the genetic composition of polygenic selection.

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Section: Introductionmentioning

confidence: 99%

Polygenic selection to a changing optimum under self–fertilisation

Hartfield,

Glémin

2024

PLoS Genet

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Genetic diversity during selective sweeps in non-recombining populations

Kaushik,

Jain,

Johri

2024

Preprint

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Selective sweeps, resulting from the spread of beneficial, neutral, or deleterious mutations through a population, shape patterns of genetic variation at linked neutral sites. While many theoretical, computational, and statistical advances have been made in understanding the genomic signatures of selective sweeps in recombining populations, substantially less is understood in populations with little/no recombination. We present a mathematical framework based on diffusion theory for obtaining the site frequency spectrum (SFS) at linked neutral sites immediately post and during the fixation of moderately or strongly beneficial mutations. We find that when a single hard sweep occurs, the SFS decays as 1/xfor low derived allele frequencies (x), similar to the neutral SFS at equilibrium, whereas at higher derived allele frequencies, it follows a 1/x2power law. These power laws are universal in the sense that they are independent of the dominance and inbreeding coefficient, and also characterize the SFS during the sweep. Additionally, we find that the derived allele frequency where the SFS shifts from the 1/xto 1/x2law, is inversely proportional to the selection strength: thus under strong selection, the SFS follows the 1/x2dependence for most allele frequencies, resembling a rapidly expanding neutral population. When clonal interference is pervasive, the SFS immediately post-fixation becomes U-shaped and is better explained by the equilibrium SFS of selected sites. Our results will be important in developing statistical methods to infer the timing and strength of recent selective sweeps in asexual populations, genomic regions that lack recombination, and clonally propagating tumor populations.

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Polygenic dynamics underlying the response of quantitative traits to directional selection

Cited by 2 publications

References 76 publications

Polygenic selection to a changing optimum under self–fertilisation

Polygenic selection to a changing optimum under self–fertilisation

Genetic diversity during selective sweeps in non-recombining populations

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