Understanding the evolutionary capacity of populations to adapt to novel environments is one of the major pursuits in genetics. Moreover, for plant breeding, maladaptation is the foremost barrier to capitalizing on intraspecific variation in order to develop new breeds for future climate scenarios in agriculture. Using a unique study design, we simultaneously dissected the population and quantitative genomic basis of short-term evolution in a tropical landrace of maize that was translocated to a temperate environment and phenotypically selected for adaptation in flowering time phenology. Underlying 10 generations of directional selection, which resulted in a 26-day mean decrease in female-flowering time, [Formula: see text] of the heritable variation mapped to [Formula: see text] of the genome, where, overall, alleles shifted in frequency beyond the boundaries of genetic drift in the expected direction given their flowering time effects. However, clustering these non-neutral alleles based on their profiles of frequency change revealed transient shifts underpinning a transition in genotype-phenotype relationships across generations. This was distinguished by initial reductions in the frequencies of few relatively large positive effect alleles and subsequent enrichment of many rare negative effect alleles, some of which appear to represent allelic series. With these genomic shifts, the population reached an adapted state while retaining [Formula: see text] of the standing molecular marker variation in the founding population. Robust selection and association mapping tests highlighted several key genes driving the phenotypic response to selection. Our results reveal the evolutionary dynamics of a finite polygenic architecture conditioning a capacity for rapid environmental adaptation in maize.

中文翻译：

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玉米环境适应短期进化的基因组基础。


了解种群适应新环境的进化能力是遗传学的主要追求之一。此外，对于植物育种来说，适应不良是利用种内变异来开发适合未来农业气候情景的新品种的最大障碍。使用独特的研究设计，我们同时剖析了热带地方品种玉米短期进化的种群和定量基因组基础，该玉米被转移到温带环境并进行表型选择以适应开花时间物候。在 10 代定向选择的基础上，导致雌性开花时间平均减少 26 天，可遗传变异的 [公式：参见文本] 映射到基因组 [公式：参见文本]，总体而言，等位基因发生了转移考虑到开花时间的影响，其频率超出了预期方向上遗传漂变的界限。然而，根据频率变化概况对这些非中性等位基因进行聚类揭示了支撑跨代基因型-表型关系转变的瞬时变化。其特点是少数相对较大的正效应等位基因的频率最初减少，随后许多罕见的负效应等位基因富集，其中一些似乎代表等位基因系列。通过这些基因组转变，种群达到了适应状态，同时保留了创始种群中固定分子标记变异的[公式：见文本]。稳健的选择和关联作图测试强调了驱动选择表型反应的几个关键基因。 我们的结果揭示了有限多基因结构的进化动力学调节了玉米快速环境适应的能力。