Data from: Adaptations between ecotypes and along environmental gradients in Panicum virgatum

Determining the patterns and mechanisms of natural selection in the wild is of fundamental importance to understanding the differentiation of populations and the evolution of new species. However, it is often unknown the extent to which adaptive genetic variation is distributed among ecotypes between distinct habitats versus along large-scale geographic environmental gradients, such as those that track latitude. Classic selection in the wild experiments in switchgrass, Panicum virgatum, tested for adaptation at both of these levels of natural variation. Here we review what these field experiments, as well as modern agronomic field trials, have taught us about natural variation and selection at both the ecotype and environmental gradient level in P. virgatum. With the recent genome sequencing efforts of P. virgatum, it is poised to become an excellent system for understanding the adaptation of grassland species across the eastern half of North America. The identification of genetic loci involved in different types of adaptations will help to understand the evolutionary mechanisms of diversification within P. virgatum and provide useful information for the breeding of high yielding cultivars for different ecoregions.

解析野生环境下自然选择的作用模式与机制，对于理解种群分化与新物种形成演化具有核心意义。然而，目前学界尚不清楚适应性遗传变异的分布格局：其更多分布于不同生境间的生态型(ecotype)之间，还是沿纬度等大尺度地理环境梯度展开。针对柳枝稷（Panicum virgatum）开展的经典野生自然选择实验，便同时检验了这两类自然变异水平下的适应性。本文综述了上述野外实验与现代农艺田间试验的研究成果，系统梳理了柳枝稷在生态型与环境梯度两个维度下的自然变异与自然选择规律。随着近期柳枝稷基因组测序工作的推进，该物种有望成为研究北美东部区域草原物种适应性演化的优质模式系统。鉴定参与不同适应性类型的遗传位点，不仅有助于解析柳枝稷种群内部分化的演化机制，还可为不同生态区域的高产栽培品种选育提供关键参考依据。