As species are fundamental units of evolutionary biology research, accurate species delimitation plays a crucial role in current biodiversity management. The Qinghai-Tibet Plateau (QTP) comprises one of the global biodiversity hotspots, and plant speciation and its evolutionary history in this region still need much research. and (Ranuculaceae) are mainly distributed in the QTP and its adjacent regions. The two species have extremely similar morphological characteristics, and their evolutionary relationship is still controversial. In this study, we collected 244 individuals in 14 populations from the main distribution areas of the two species. Genome-wide single-nucleotide polymorphisms (SNPs) from genotyping-by-sequencing (GBS) of and were obtained to decipher the taxonomic delimitation and explore the evolutionary history. We performed neighbor-joining (NJ), PCA, structure, and niche overlap analyses. None of them support that and can be considered as two separate species. In addition, the genetic difference between species is less than that among populations. We propose merging the two species into one. We also found that the genetic difference between the two species was not associated with morphological species or geographic distance. Gene flow and genetic drift may play a crucial role in weakening the correlation between genetic distance and geographical distance. A bottleneck effect occurred in the two species during the last glacial maximum. Based on the Maxent and Stairway Plot results, we inferred that and still had large survival ranges during the LGM, similar to other cold-tolerant species. Furthermore, human activity, such as overexploitation causing habitat fragmentation, might be one of the factors that threat to the survival of and in the current period.

中文翻译：

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种群遗传学和生态位模型揭示了乌头和黄乌头的物种边界和进化历史

由于物种是进化生物学研究的基本单位，准确的物种界定在当前的生物多样性管理中发挥着至关重要的作用。青藏高原是全球生物多样性热点地区之一，该地区的植物物种形成及其进化历史仍需要大量研究。毛茛科（Ranuculaceae）主要分布于青藏高原及其邻近地区。这两个物种的形态特征极为相似，其进化关系仍存在争议。在这项研究中，我们从这两个物种的主要分布区收集了14个种群的244只个体。通过测序基因分型 (GBS) 获得全基因组单核苷酸多态性 (SNP)，以破译分类界限并探索进化历史。我们进行了邻接 (NJ)、PCA、结构和生态位重叠分析。他们都不支持这一点，并且可以被视为两个不同的物种。此外，物种间的遗传差异小于种群间的遗传差异。我们建议将这两个物种合并为一个。我们还发现，两个物种之间的遗传差异与形态物种或地理距离无关。基因流动和遗传漂变可能在削弱遗传距离和地理距离之间的相关性方面发挥着至关重要的作用。在末次盛冰期，这两个物种出现了瓶颈效应。根据 Maxent 和 Stairway 图结果，我们推断在末次盛冰期期间， 和 仍然有很大的生存范围，与其他耐寒物种类似。此外，人类活动，例如过度开发导致栖息地破碎化，可能是威胁当前时期生存的因素之一。