The best of both worlds: Combining population genetic and quantitative genetic models

Dekens, Léonard; Otto, Sarah P.; Cálvez, Vincent

doi:10.1016/j.tpb.2022.10.002

Cited by 6 publications

(8 citation statements)

References 40 publications

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“…Our next step will be to study the adaptation of an age–structured population to a changing environment, following (Cotto and Ronce, 2014). Other modes of reproduction with a more complicated genetic underlying architecture are also under investigation, (see for instance Dekens and Mirrahimi, 2021; Dekens et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

Adaptation of a quantitative trait to a changing environment: new analytical insights on the asexual and infinitesimal sexual models

Garnier

Cotto

Bourgeron³

et al. 2022

Preprint

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Predicting the adaptation of populations to a changing environment is crucial to assess the impact of human activities on biodiversity. Many theoretical studies have tackled this issue by modeling the evolution of quantitative traits subject to stabilizing selection around an optimum phenotype, whose value is shifted continuously through time. In this context, the population fate results from the equilibrium distribution of the trait, relative to the moving optimum. Such a distribution may vary with the shape of selection, the system of reproduction, the number of loci, the mutation kernel or their interactions. Here, we develop a methodology that provides quantitative measures of population maladaptation and potential of survival directly from the entire profile of the phenotypic distribution, without any a priori on its shape. We investigate two different models of reproduction (asexual and infinitesimal sexual models of inheritance), with general forms of selection. {In particular, we recover that fitness functions such that selection weakens away from the optimum lead to evolutionary tipping points, with an abrupt collapse of the population when the speed of environmental change is too high. Our unified framework furthermore allows highlighting the underlying mechanisms that lead to this phenomenon.} More generally, it allows discussing similarities and discrepancies between the two reproduction models, the latter being ultimately explained by different constraints on the evolution of the phenotypic variance. We demonstrate that the mean fitness in the population crucially depends on the shape of the selection function in the sexual infinitesimal model, in contrast with the asexual model. In the asexual model, we also investigate the effect of the mutation kernel and we show that kernels with higher kurtosis tend to reduce maladaptation and improve fitness, especially in fast changing environments.

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Section: Discussionmentioning

confidence: 99%

Adaptation of a quantitative trait to a changing environment: new analytical insights on the asexual and infinitesimal sexual models

Garnier

Cotto

Bourgeron³

et al. 2022

Preprint

Self Cite

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“…A second major caveat is our neglect of linkage disequilibrium (Lande, 1981;Schneemann et al, 2020), which is essential to studying the full dynamics of introgression. Nevertheless, even the current results have suggestive implications for the stability of local adaptation, and the evolution of genetic architectures (Dekens et al, 2021;Yeaman, 2022). For example, the dominance of alleles may be a major determinant of the effective rates of migration between demes, and the possibility of allele swamping (Barton, 1992).…”

Section: Discussionmentioning

confidence: 69%

How does the mode of evolutionary divergence affect reproductive isolation?

Sanctis

Schneemann

Welch

2022

Preprint

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When divergent populations interbreed, the outcome will be affected by the genomic and phenotypic differences that they have accumulated. In this way, the mode of evolutionary divergence between populations may have predictable consequences for the fitness of their hybrids, and so for the progress of speciation. To investigate these connections, we present a new analysis of hybridization under Fisher’s geometric model. Unlike previous such analyses, we derive results using combinatorics, and so we make few assumptions about the additive and dominance effects that differentiate the hybridizing populations. Results show that the strength and form of postzygotic reproductive isolation (RI) depend on just two properties of the fixed effects, which we call the “total amount” and “net effect” of evolutionary change. It follows that identical patterns of RI can arise in different ways. Nevertheless, the key quantities do contain information about the history of divergence, and the dominance and additive effects contain complementary information. Our results also clarify the roles of large- and small-effect substitutions in generating RI. For example, when hybridizing populations are locally adapted, populations that adapted with a few large-effect mutations will show more intrinsic RI than populations that followed the same phenotypic trajectory, but with many small mutations.

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“…A second major caveat is our neglect of linkage disequilibrium (Lande, 1981;Schneemann, De Sanctis, et al, 2020), which is essential to studying the full dynamics of introgression. Nevertheless, even the current results have suggestive implications for the stability of local adaptation, and the evolution of genetic architectures (Dekens et al, 2022;Yeaman, 2022). For example, the dominance of alleles may be a major determinant of the effective rates of migration between demes, and the possibility of allele swamping (Barton, 1992).…”

Section: If M(a A)−m(mentioning

confidence: 69%

How does the mode of evolutionary divergence affect reproductive isolation?

Sanctis¹,

Schneemann²,

Welch³

2023

Peer Community Journal

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When divergent populations interbreed, the outcome will be affected by the genomic and phenotypic differences that they have accumulated. In this way, the mode of evolutionary divergence between populations may have predictable consequences for the fitness of their hybrids, and so for the progress of speciation. To investigate these connections, we present a new analysis of hybridization under Fisher's geometric model, making few assumptions about the allelic effects that differentiate the hybridizing populations. Results show that the strength and form of postzygotic reproductive isolation (RI) depend on just two properties of the evolutionary changes, which we call the "total amount" and "net effect" of change, and whose difference quantifies the similarity of the changes at different loci, or their tendency to act in the same phenotypic direction. It follows from our results that identical patterns of RI can arise in different ways, since different evolutionary histories can lead to the same total amount and net effect of change. Nevertheless, we show how these estimable quantities do contain some information about the history of divergence, and that -thanks to Haldane's Sieve -the dominance and additive effects contain complementary information.

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The best of both worlds: Combining population genetic and quantitative genetic models

Cited by 6 publications

References 40 publications

Adaptation of a quantitative trait to a changing environment: new analytical insights on the asexual and infinitesimal sexual models

Adaptation of a quantitative trait to a changing environment: new analytical insights on the asexual and infinitesimal sexual models

How does the mode of evolutionary divergence affect reproductive isolation?

How does the mode of evolutionary divergence affect reproductive isolation?

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