Tests of the predictability of population genetic structure and change in wild animal populations

进化是种群遗传组成随时间变化的结果。导致种群遗传变化的许多过程与生态条件密切相关。例如，如果环境变异阻碍了行动，它会导致种群在遗传上疏远；如果在不同的环境中选择不同的特征，环境变异可能会导致种群适应性地分化。因此，了解生态学如何产生种群遗传变化是理解自然界进化模式的核心。我的研究将种群基因组学与进化生态学相结合，以解释种群遗传结构的形成、持续、崩溃和随时间变化的方式。我将用灰松鼠(Sciurus Carolinensis)对城市的殖民来回答我的问题。城市化使人口碎片化，塑造了扩散模式，改变了选择压力，并在空间中复制。这使得灰松鼠对城市的殖民成为研究当代进化的理想背景。 这一探索资助周期I将解决关于适应种群分化进程的早期阶段的问题。我将探索：1)对遗传变异的选择的可预测性；2)在与不同适应的种群杂交时，种群是否会出现分化，以及分化程度有多大；以及3)在假定选择的位置附近的高重组率是否会通过暴露新的基因组合进行选择而提高新环境中的选择效率。 解决这些问题将需要全基因组分子标记的综合分析、全基因组分析和深入的实地生态研究。因此，我的项目将培养生物信息学、统计种群遗传学、种群生态学和野外监测技能方面的高素质人才。我们将从成对的城市森林地点抽取松鼠样本，以量化平行选择，确定城市适应的候选基因座，并对人口统计学差异进行建模。我们将使用在一个重点地点的密集田野调查数据来模拟取决于环境和基因类型的生存和繁殖。然后，通过对来自这个焦点位置的个体进行全基因组重测序，我们将测试候选基因座附近的高重组率是否有助于局部适应。 通过研究当代进化变化，我们将了解种群分化的早期阶段。由于人类活动对自然环境的广泛和加速影响，这项研究对保护和管理科学也将是重要的。据预测，2000年至2030年期间，城市土地覆盖率将增加两倍。鉴于城市的扩张和持续，了解城市化对自然人口的进化影响对于规划将人类活动对自然人口的负面影响降至最低将是重要的。

Evolution is the result of changes in the genetic composition of populations through time. Many of the processes that cause population genetic change are intimately tied to ecological conditions. For example, environmental variation causes populations to drift apart genetically if it impedes movement and can cause populations to diverge adaptively if different traits are selected in different environments. Thus, understanding how ecology produces population genetic change is central to understanding evolutionary patterns in nature. My research integrates population genomics with evolutionary ecology to explain the ways that population genetic structures form, persist, collapse, and change through time. I willuse the colonisations of cities by grey squirrels (Sciurus carolinensis) to address my questions. Urbanisation fragments populations, shapes dispersal patterns, alters selective pressures, and is replicated in space. This makes the colonisation of cities by grey squirrels an ideal setting to study contemporary evolution. This Discovery Grant cycle I will address questions about the early stages of the process of adaptive population divergence. I will explore: 1) the predictability of selection on genetic variants; 2) whether, and by how much, populations can diverge while interbreeding with differently adapted populations; and 3) whether high recombination rates near putatively selected loci increase the efficiency of selection in new environments by exposing new gene combinations to selection. Addressing these questions will require integrated analyses of genome-wide molecular markers, whole genome analyses, and intensive field based ecological study. Thus, my program will train highly qualified personnel in bioinformatics, statistical population genetics, population ecology, and field monitoring skills. We will sample squirrels from paired city-forest sites to quantify parallel selection, identify candidate loci for urban adaptation, and model the demographics of divergence. We will use data from intensive fieldwork at a focal site to model survival and reproduction contingent upon environments and genotypes. Then, with whole genome resequencing of individuals from this focal site we will test whether high recombination rates near candidate loci facilitate local adaptation. By studying contemporary evolutionary change we will learn about the early stages of population divergence. Due to the extensive and accelerating effects of human activities on natural environments this research will also be important for conservation and management science. Urban land cover is predicted to triple between 2000 and 2030. Given the expansion and persistence of cities, understanding the evolutionary effects of urbanisation on natural populations will be important for planning to minimise the negative effects of human activities on natural populations.