Adaptive introgression in the Anthropocene

人类迁移物种和人为气候变化导致了有史以来最快的物种分布变化率，导致许多本地和非本地物种聚集在一起。虽然生态后果往往是有据可查的，但本地和非本地物种之间的杂交和基因流动的进化影响通常不太明显。然而，本地和非本地物种之间的基因流动可能会深刻影响未来的进化适应和多样化，可能影响物种保护，应对气候变化和入侵物种的传播。以前的研究只集中在几个典型物种之间的基因流。因此，我们对物种间基因流动的普遍性和影响缺乏总体了解，尤其是人类活动如何改变基因流动的速率。在这项雄心勃勃的计划中，我们将利用达尔文生命之树项目产生的参考基因组，并将高通量测序与最新的生物信息学方法相结合，以解决一个日益重要的主要问题：本地和非本地开花植物物种之间的基因流动程度如何？这种基因流动对本地或非本地物种是否具有适应价值？我们将第一次评估基因流的主要分支的生命之树使用所有106本地/非本地开花植物物种对已知的杂交在不列颠群岛。然后，我们将使用这些数据来参数化模型，预测本地和非本地物种之间的基因流的速率，并测试模型估计尚未观察到杂交的物种对之间的隐性基因流。英国的植物群被深入研究，其良好的特征分布，杂交和生态学使其成为一个理想的模型系统，以建立预测模型，探索影响本地和非本地物种之间基因流动的速率和影响的生态和遗传因素。在这个项目的过程中，我们将产生24万亿碱基的序列数据，包括来自269种开花植物的741个个体的基因组（137个本地的，132个非本地的）。我们将使用这些数据首先评估所有106个本地/非本地开花植物物种对之间的基因流的程度，已知在不列颠群岛杂交（目标1），并建立是否最近在这些物种中看到的范围扩大与增加基因流（目标2）。然后将使用群体样本评估目标1和2中显示适应性渐渗迹象的10个受体物种子集中适应性基因流的证据（目标3）。我们将使用目标1和目标2中的渐渗估计值来建立统计模型，以了解影响基因流的遗传和生态因素（目标4）。最后，我们将测试评估模型预测的准确性，不知道杂交使用额外的经验估计的基因流从17个属的菊科（雏菊科）和禾本科（草）（目标5）的物种之间的隐藏基因流。该项目将是理解人类介导的物种间基因流动的进化后果的重要一步。种间杂交很可能是广泛的，但基因流动可能仍然受到限制，因为后合子生殖障碍。另一方面，物种之间的基因流动可能是常见的，并具有很强的适应性后果。除了学术受益者（进化和全球变化生物学家），我们的研究结果将告知保护从业者，控制入侵物种，并提高公众对物种间基因流的普遍性和重要性的认识，以及对环境变化的进化反应。

Human translocation of species and anthropogenic climate change are resulting in some of the fastest rates of species distribution changes ever seen, causing many native and non-native species to be brought together. While the ecological consequences are often well-documented, the evolutionary impacts of hybridization and gene flow between native and non-native species are usually less visible. Yet gene flow between native and non-native species could profoundly affect future evolutionary adaptations and diversification, potentially impacting on species conservation, responses to climate change and the spread of invasive species. Previous studies have only focussed on gene flow between a few exemplar species. So we lack a general understanding of the prevalence and impact of interspecific gene flow across the tree of life, and specifically of how human activities may be altering these rates of gene flow.In this ambitious proposal, we will leverage reference genomes produced by the Darwin Tree of Life project and combine high-throughput sequencing with the latest bioinformatic methods to address a major question of growing importance: What is the extent of gene flow between native and non-native flowering plant species, and is this gene flow of adaptive value to native or non-native species? We will for the first time assess gene flow across a major branch of the tree of life using all 106 native/non-native flowering plant species pairs known to be hybridising in the British Isles. We will then use these data to parameterise models predicting the rate of gene flow between native and non-native species, and test model estimates of cryptic gene flow among species pairs that have not been observed to hybridize. The British flora is intensively studied, and its well characterised distributions, hybrids and ecology make it an ideal model system to build predictive models exploring ecological and genetics factors affecting the rates and effects of gene flow between native and non-native species.Over the course of this project we will generate 24 trillion bases of sequence data, comprising the genomes of 741 individuals from 269 flowering plant species (137 native, 132 non-native). We will use this data to first assess the extent of gene flow between all 106 native/non-native flowering plant species pairs that are known to hybridise in the British Isles (Objective 1), and establish whether the recent range expansions seen in some of these species are associated with increased gene flow (Objective 2). Population samples will then be used to assess evidence for adaptive gene flow in a subset of 10 recipient species that from Objective 1 and 2 show indications of adaptive introgression (Objective 3). We will use the estimates of introgression from Objectives 1 and 2 to build statistical models to understand the genetic and ecological factors affecting gene flow (Objective 4). Finally, we will test assess the accuracy of model predictions of cryptic gene flow between species that are not known to hybridize using additional empirical estimates of gene flow from 17 genera of Asteraceae (daisy family) and Poaceae (grasses) (Objective 5). This project will be a major step towards understanding the evolutionary consequences of human-mediated gene flow between species. Interspecific hybridization could well be widespread, yet gene flow may still be restricted because of postzygotic reproductive barriers. Alternatively, gene flow between species may be common, and with strong fitness consequences. In addition to academic beneficiaries (evolutionary and global change biologists), our results will inform conservation practitioners, control of invasive species, and increase awareness in the general public about the ubiquity and importance of gene flow among species, and evolutionary responses to environmental change.