The genus Dracaena in Macaronesia comprises two threatened species of arborescent monocots that are often associated with one of the most intriguing biogeographic disjunctions: the Rand Flora pattern. Molecular information is, however, largely missing for the Macaronesian Dracaena taxa (“MDT”, hereafter), and the biogeographic or population genetic patterns of this lineage have not yet been thoroughly assessed. To fill this gap, we generated plastid DNA sequence data of 14 Dracaena populations representing the entire natural distribution of MDT (including mainland Morocco and all recognized subspecies), 9 additional populations of subspontaneous origin, and a set of related species of the genus. We performed phylogenetic, biogeographic, and population genetic analyses at different spatial scales and conducted a comparative review on plant haplotype diversity in Macaronesian plants. The results of our phylogenetic analyses indicated the monophyly of the MDT and an origin separate from a clade of geographically distant species that so far were postulated as their closest living relatives (D. cinnabari, D. ombet, D. schizantha, D. serrulata). The results of our phylogeographic analyses indicated that diversification within D. draco occurred throughout the Pleistocene and that wild peripheral populations (Madeira, mainland Morocco) may have a recent origin from Canarian source populations. Recent dispersals, coupled with remarkably low levels of haplotype diversity, probably account for the weak phylogeographic signal observed across wild populations. However, our results suggested that human‐assisted expansion of Dracaena inflates the extant phylogeographic signal by non‐random translocation of a specific subset of haplotypes. Our study demonstrates that many of the previous biogeographic scenarios on MDT are not supported by molecular data. Instead, our results highlight (i) the impact that human activity may have on the phylogeographic pattern of island plants, and (ii) the need of a deeper taxonomic sampling in future investigations on MDT and close relatives.

中文翻译：

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标志性，受威胁但基本上未知的：从质体DNA标记推断出的马卡龙龙树（Dracaena spp。）的生物地理

Macaronesia中的龙血树属（Dracaena）包括两个受威胁的树状单子叶植物，它们通常与最有趣的生物地理学分离之一有关：Rand Flora模式。然而，Macaronesian Dracaena类群（以下简称“ MDT”）的分子信息已大大缺失，并且尚未对该谱系的生物地理或种群遗传模式进行全面评估。为了填补这一空白，我们生成了14个龙血树的质体DNA序列数据代表MDT整个自然分布的种群（包括摩洛哥大陆和所有公认的亚种），9个亚自然起源的种群以及一组该属的相关物种。我们在不同的空间尺度上进行了系统发育，生物地理和种群遗传分析，并对马卡龙植物的单倍型多样性进行了比较审查。我们的系统发育分析的结果表明了MDT和起源的单系从迄今被假定为自己最亲近的亲戚（相距遥远物种的进化枝分开D. cinnabari，D. ombet，D. schizantha，D.石楠）。我们的系统地理学分析的结果表明内的多样化D.德拉科发生在整个更新世和野生种群外设（马德拉，大陆摩洛哥）可能从加那利源种群最近的起源。最近的传播，再加上单倍型多样性水平极低，可能是造成野生种群中较弱的植物学信号的原因。但是，我们的结果表明，人为辅助的龙血树扩展通过单倍型特定子集的非随机易位，夸大了现有的地理信息。我们的研究表明，分子数据不支持MDT上许多以前的生物地理场景。相反，我们的结果强调了（i）人类活动可能对岛上植物的地理格局产生的影响，以及（ii）在今后对MDT和近亲的调查中需要进行更深层次的分类抽样。