Data from: Population genomic analyses reveal a history of range expansion and trait evolution across the native and invaded range of yellow starthistle (Centaurea solstitialis)

Identifying sources of genetic variation and reconstructing invasion routes for non-native introduced species is central to understanding the circumstances under which they may evolve increased invasiveness. In this study, we used genome-wide single nucleotide polymorphisms to study the colonization history of Centaurea solstitialis in its native range in Eurasia and invasions into the Americas. We leveraged this information to pinpoint key evolutionary shifts in plant size, a focal trait associated with invasiveness in this species. Our analyses revealed clear population genomic structure of potential source populations in Eurasia, including deep differentiation of a lineage found in the southern Apennine and Balkan Peninsulas and divergence among populations in Asia, eastern Europe, and western Europe. We found strongest support for an evolutionary scenario in which western European populations were derived from an ancient admixture event between populations from eastern Europe and Asia, and subsequently served as the main genetic ‘bridgehead’ for introductions to the Americas. Introductions to California appear to be from a single source region, and multiple, independent introductions of divergent genotypes likely occurred into the Pacific Northwest. Plant size has evolved significantly at three points during range expansion, including a large size increase in the lineage responsible for the aggressive invasion of California's interior. These results reveal a long history of colonization, admixture, and trait evolution in C. solstitialis, and suggest routes for improving evidence-based management decisions for one of the most ecologically and economically damaging invasive species in the western United States.识别外来入侵物种的遗传变异来源并重构其入侵路径，是解析其演化出更强入侵性的核心前提。本研究利用全基因组单核苷酸多态性（genome-wide single nucleotide polymorphisms）标记，解析了黄星蓟（Centaurea solstitialis）在欧亚大陆原生分布区的定殖历史，以及其入侵美洲的过程。本研究依托该数据，精准定位了该物种与入侵性相关的核心性状——植株体型的关键演化转变事件。群体基因组分析结果显示，欧亚大陆的潜在源种群具有清晰的遗传结构：亚平宁半岛南部与巴尔干半岛的支系存在深度遗传分化，亚洲、东欧与西欧的种群间也存在显著遗传分歧。本研究得到最有力的演化支持证据：西欧种群起源于东欧与亚洲种群间的古老遗传渐渗事件，并随后成为美洲入侵种群的主要遗传‘桥头堡’。加州的入侵种群似乎仅起源于单个源种群区域，而太平洋西北地区则存在多个独立引入的不同遗传型种群。在分布区扩张过程中，植株体型共发生了三次显著的演化转变，其中驱动加州内陆地区恶性入侵的支系，其植株体型出现了大幅提升。本研究结果揭示了黄星蓟漫长的定殖、遗传渐渗与性状演化历史，并为美国西部生态与经济危害最严重的入侵物种之一的循证管理决策优化提供了可行路径。