Adaptive introgression in the Anthropocene

人类对物种的转移和人为气候变化正在导致物种分布变化的一些速度是有史以来最快的，导致许多本地和非本地物种汇聚在一起。虽然生态后果通常是有据可查的，但本地和非本地物种之间的杂交和基因流动对进化的影响通常不太明显。然而，本土物种和非本土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性，可能会对物种保护、对气候变化的反应和入侵物种的传播产生影响。以前的研究只关注少数几个样本物种之间的基因流动。在这个雄心勃勃的提案中，我们将利用达尔文生命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具有适应价值吗？我们将首次使用在不列颠群岛杂交的所有106种本地/非本地开花植物对来评估跨越生命树的一个主要分支的基因流动。然后，我们将使用这些数据来对预测本地和非本地物种之间的基因流动速度的模型进行参数化，并测试尚未观察到杂交的物种对之间隐蔽基因流动的模型估计。英国植物区系得到了深入的研究，其良好的分布、杂交和生态使其成为建立预测模型的理想模型系统，该模型探索影响本地和非本地物种之间基因流动速度和效果的生态和遗传因素。在这个项目的过程中，我们将生成24万亿个碱基的序列数据，包括来自269个开花植物物种(137个本地植物，132个非本地植物)的741个个体的基因组。我们将使用这些数据首先评估不列颠群岛已知的106个本地/非本地开花植物物种对之间的基因流动程度(目标1)，并确定其中一些物种最近出现的范围扩大是否与增加的基因流动有关(目标2)。然后，将使用种群样本来评估来自目标1和目标2的10个受体物种子集的适应性基因流的证据，这些子集显示出适应性导入的迹象(目标3)。我们将使用目标1和目标2的渐渗估计来建立统计模型，以了解影响基因流动的遗传和生态因素(目标4)。最后，我们将使用来自菊科(雏菊科)和禾本科(禾本科)17个属的额外经验估计来测试评估模型预测未知杂交物种之间隐蔽基因流动的准确性(目标5)。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。种间杂交可能很普遍，但由于合子后生殖障碍，基因流动可能仍然受到限制。或者，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。除了学术上的受益者(进化论和全球变化生物学家)，我们的成果还将为保护从业者、入侵物种的控制提供信息，并提高公众对物种间基因流动的普遍性和重要性以及对环境变化的进化反应的认识。

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.