Data from: Introduced Scotch broom (Cytisus scoparius) invades the genome of native populations in vulnerable heathland habitats

Cytisus scoparius is a global invasive species that affects local flora
and fauna at the intercontinental level. Its natural distribution spans
across Europe, but seeds have also been moved among countries, mixing
plants of native and non-native genetic origins. Hybridization between the
introduced and native gene pool is likely to threaten both the native gene
pool and the local flora. In this study, we address the potential threat
of invasive C. scoparius to local gene pools in vulnerable heathlands. We
used nuclear single nucleotide polymorphic (SNP) and simple sequence
repeat (SSR) markers together with plastid SSR and indel markers to
investigate the level and direction of gene flow between invasive and
native heathland C. scoparius. Analyses of population structures confirmed
the presence of two gene pools: one native and the other invasive. The
nuclear genome of the native types was highly introgressed with the
invasive genome, and we observed advanced-generation hybrids, suggesting
that hybridization has been occurring for several generations. There is
asymmetrical gene flow from the invasive to the native gene pool, which
can be attributed to higher fecundity in the invasive individuals,
measured by the number of flowers and seed pods. Strong spatial genetic
structure in plastid markers and weaker structure in nuclear markers
suggest that seeds spread over relatively short distances and that gene
flow over longer distances is mainly facilitated by pollen dispersal. We
further show that the growth habits of heathland plants become more
vigorous with increased introgression from the invaders. Implications of
the findings are discussed in relation to future management of invading C.
scoparius.

金雀花（Cytisus scoparius）是一种全球性入侵物种，可在洲际尺度上对本地动植物区系造成显著负面影响。该物种的自然分布范围覆盖欧洲，但其种子被人为跨国家传播后，导致本地与外来遗传背景的植株发生混合。入侵种群与本地种群的基因库之间发生的杂交事件，可能同时对本地基因库及本地植物群落构成威胁。本研究聚焦于入侵性金雀花对脆弱石楠灌丛中本地基因库的潜在威胁。研究团队采用核基因组单核苷酸多态性（Single Nucleotide Polymorphism, SNP）标记、简单序列重复（Simple Sequence Repeat, SSR）标记，结合质体SSR标记与插入缺失（insertion-deletion, indel）标记，探究入侵与本地石楠灌丛中金雀花种群间基因流的水平与方向。种群结构分析证实存在两类基因库，分别对应本地种群与入侵种群。本地种群的核基因组已被入侵基因组高度渐渗，且研究检测到多代杂交后代，表明杂交事件已持续多代。基因流呈现从入侵种群向本地种群的不对称性，这可归因于入侵个体更高的繁殖力——该繁殖力可通过花量与荚果数量进行量化。质体标记呈现显著的空间遗传结构，而核标记的空间结构较弱，这表明种子传播距离相对较短，长距离基因流主要依赖花粉传播实现。本研究进一步发现，随着入侵种群渐渗程度的提升，石楠灌丛中金雀花的生长态势愈发旺盛。最后，本文讨论了该研究结果对金雀花未来防控管理的启示。