Polygenic Adaptation and Quantitative Trait Dynamics

Polygenic adaptation describes evolutionary change in which many genetic variants, each of small effect, collectively shift in frequency to produce a phenotypic response to selection. Quantitative traits, such as height, stress tolerance or yield, are governed by numerous loci whose individual contributions sum to determine the trait value. Adaptation can proceed by subtle adjustments in allele frequencies across the entire genomic basis or by more pronounced sweeps at a few loci of larger effect. The dynamics of this process depend on the genetic architecture—the number, effect sizes and distribution of contributing alleles—as well as the interplay between selection strength, mutation input and random genetic drift. Recent theoretical advances have clarified how a single compound parameter, integrating mutation rates and redundancy among loci, predicts whether adaptation will resemble a collective polygenic shift, sequential selective sweeps or an intermediate oligogenic pattern. Empirical investigations, leveraging genome-wide association studies and population genomics, have begun to detect polygenic signals of adaptation in natural and agricultural populations. Insights into these dynamics are crucial for understanding rapid responses to changing environments, improving crop and livestock breeding strategies and predicting the evolutionary trajectories of wild populations under global change.

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Polygenic Adaptation and Quantitative Trait Dynamics publication trend

The graph below shows the total number of articles in polygenic adaptation and quantitative trait dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Polygenic adaptation: Evolutionary change driven by coordinated allele-frequency shifts at many loci of small effect.

Quantitative trait: A heritable characteristic measured on a continuous scale and influenced by multiple genetic and environmental factors.

Genetic architecture: The number, effect sizes and interactions of loci underlying a trait.

Selective sweep: A rapid increase in frequency of a beneficial allele, often reducing genetic variation at linked loci.

Allele frequency: The proportion of copies of a particular genetic variant in a population.

Stabilising selection: A form of natural selection favouring intermediate trait values and acting against extremes.

References

1. A theory of oligogenic adaptation of a quantitative trait. Genetics (2023).
2. Polygenic adaptation: From sweeps to subtle frequency shifts. PLOS Genetics (2019).
3. Evolution of polygenic traits under global vs local adaptation. Genetics (2022).
4. From genotype to phenotype: Genetic redundancy and the maintenance of an adaptive polymorphism in the context of high gene flow. Evolution Letters (2022).