Phenotypic and genetic variation in Biscutella didyma and other Brassicaceae and adaptation to environmental change - a combined ecological-genomic approach

局部适应和地理分离对多样性的进化至关重要，最近的人类全基因组分析揭示了遗传差异空间分布的证据。然而，形成这些模式的力量只在少数情况下被理解，因为人们通常不知道遗传分化最初是如何产生的。自顶向下的方法可以指出在最近的过去被选择的基因组区域，但它们很少确定负责的基因和被选择的性状。相反，关于局部适应的生态学研究很少利用基因组学的进展。本研究将现代进化生态学与最先进的基因组学相结合，研究了十字花科植物和其他芸苔科植物的实时进化。我们利用一个独特的野外实验来测试沿干旱梯度的全基因组分化，研究在暴露于操纵降水制度的人群中是否可以检测到全基因组选择特征，以及响应选择梯度的表型变异性是否符合理论预测。在第一阶段研究结果的基础上，我们将研究三种独立干旱菌株和四种相关物种的全基因组选择特征。此外，我们将沿着梯度对另外六个相关物种进行表型分析。我们将把我们的性状测量扩展到已知的遗传途径和沿气候梯度呈现曲线的新性状：气孔和毛状体密度、草食防御和自交率。通过关注具有良好特征的遗传网络的适应性性状，我们不仅可以确定选定的基因，还可以回答如何在独立比较中实现适应潜力。我们的发现将使我们能够开发预测气候变化下的适应能力模型。

Local adaptation and geographic separation are crucial for the evolution of diversity, and recent whole-genome analyses in humans have revealed evidence for spatial distribution of genetic differences. The forces shaping these patterns are, however, only understood in few cases, because it is generally not known how genetic differentiation arises in the first place. Top-down approaches can point to regions of the genome under selection in the recent past, but they rarely identify the responsible genes and the selected traits. Conversely, ecological studies on local adaptation have made little use of the progress in genomics. Here, we combine modern evolutionary ecology with state-of-the-art genomics to study real-time evolution in Biscutella didyma and other Brassicaceae species. We utilize a unique field experiment to test genome-wide differentiation along an aridity gradient, study whether genome-wide signatures of selection are detectable in populations that have been exposed to manipulated precipitation regimes, and whether phenotypic variability in response to selection gradients corresponds to theoretical predictions. Building on the results from phase one, we will study genome-wide selection signature in three independent aridity clines in B. didyma and four related species. In addition, we will phenotype another six related species along the gradients. We will expand our trait measurements to new traits for which genetic pathways are well-known and which exhibit clines along the climate gradient: stomata and trichome density, herbivore defense, and selfing rates. By focusing on adaptive traits with well-characterized genetic networks, we will not only identify selected genes, but answer to how adaptive potential is being realized in independent comparisons. Our findings will enable us to develop models of adaptive capacity under predicted climate change.