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.

鉴定外来引入物种的遗传变异来源并重建其入侵路径，是解析该物种演化出更高入侵性相关机制的核心研究内容。本研究采用全基因组单核苷酸多态性（genome-wide single nucleotide polymorphisms）标记，对黄星蓟（Centaurea solstitialis）在欧亚大陆原生分布区的定居历史以及其向美洲的入侵过程开展研究。本研究依托该基因组数据，精准定位了该物种与入侵性相关的核心性状——植株体型演化的关键转变节点。分析结果显示，欧亚大陆的潜在源种群具有清晰的群体基因组结构：包括亚平宁半岛南部与巴尔干半岛南部支系的深度遗传分化，以及亚洲、东欧与西欧种群间的遗传分歧。本研究结果最有力地支持如下演化场景：西欧种群起源于东欧与亚洲种群间的古老基因渐渗事件，随后成为向美洲引种的主要遗传“桥头堡”。向加利福尼亚州的引种似乎仅起源于单个源种群区域，而向太平洋西北地区的引种则存在多起独立的、携带不同遗传型的引种事件。在分布区扩张过程中，植株体型共在三个演化节点发生了显著改变，其中负责恶性入侵加利福尼亚内陆区域的支系出现了植株体型的大幅增长。本研究结果揭示了黄星蓟（Centaurea solstitialis）长期的定居、基因渐渗与性状演化历史，并为改善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提供了可行方向。