In molecular population genetics, adaptation is typically thought to occur via selective sweeps, where targets of selection have independent effects on the phenotype and rise to fixation, whereas in quantitative genetics, many loci contribute to the phenotype and subtle frequency changes occur at many loci during polygenic adaptation. The sweep model makes specific predictions about frequency changes of beneficial alleles and many test statistics have been developed to detect such selection signatures. Despite polygenic adaptation is probably the prevalent mode of adaptation, because of its traditional focus on the phenotype, we are lacking a solid understanding of the similarities and differences of selection signatures under the two models. Recent theoretical and empirical studies have shown that both selective sweep and polygenic adaptation models could result in a sweep-like genomic signature, therefore additional criteria are needed to distinguish the two models. With replicated populations and time series data, experimental evolution studies have the potential to identify the underlying model of adaptation. Using the framework of experimental evolution, we performed computer simulations to study the pattern of selected alleles for two models: 1) adaptation of a trait via independent beneficial mutations that are conditioned for fixation, i.e. selective sweep model and 2) trait optimum model (polygenic adaptation), that is adaptation of a quantitative trait under stabilizing selection after a sudden shift in trait optimum. We identify several distinct patterns of selective sweep and trait optimum models in populations of different sizes. These features could provide the foundation for development of quantitative approaches to differentiate the two models.

中文翻译：

---

进化和重测序研究中选择性扫描和多基因适应的独特模式。


在分子群体遗传学中，适应通常被认为是通过选择性扫描发生的，其中选择的目标对表型具有独立影响并上升到固定，而在定量遗传学中，许多基因座对表型有贡献，并且在许多基因座发生微妙的频率变化时，多基因适应。扫描模型对有益等位基因的频率变化做出具体预测，并且已经开发了许多测试统计数据来检测此类选择特征。尽管多基因适应可能是普遍的适应模式，但由于其传统上关注表型，我们对这两种模型下选择特征的异同缺乏深入的了解。最近的理论和实证研究表明，选择性扫描和多基因适应模型都可能产生类似扫描的基因组特征，因此需要额外的标准来区分这两种模型。通过复制种群和时间序列数据，实验进化研究有可能确定潜在的适应模型。使用实验进化的框架，我们进行计算机模拟来研究两个模型的选定等位基因的模式：1）通过固定的独立有益突变来适应性状，即选择性扫描模型和2）性状最佳模型（多基因）适应），即在最佳性状突然发生变化后，在稳定选择下对数量性状的适应。我们在不同规模的种群中确定了几种不同的选择性扫描模式和性状最佳模型。这些特征可以为开发区分这两种模型的定量方法奠定基础。