Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
Key Laboratory of Plant Resources Conservation and Utilization, College of Biology and Environmental Sciences, Jishou University, Jishou, Hunan, 416000, China.
Sci Rep. 2017 Oct 17;7(1):13411. doi: 10.1038/s41598-017-13543-5.
To assess the role of the Qinghai-Tibetan Plateau uplift in shaping the intercontinental disjunction in Northern Hemisphere, we analyzed the origin and diversification within a geological timeframe for two relict herbaceous genera, Theligonum and Kelloggia (Rubiaceae). Phylogenetic relationships within and between Theligonum and Kelloggia as well as their relatives were inferred using five chloroplast markers with parsimony, Bayesian and maximum-likelihood approaches. Migration routes and evolution of these taxa were reconstructed using Bayesian relaxed molecular clock and ancestral area reconstruction. Our results suggest the monophyly of each Theligonum and Kelloggia. Eastern Asian and North American species of Kelloggia diverged at ca.18.52 Mya and the Mediterranean species of Theligonum diverged from eastern Asian taxa at ca.13.73 Mya. Both Kelloggia and Theligonum are Tethyan flora relicts, and their ancestors might have been occurred in warm tropical to subtropical environments along the Tethys coast. The Qinghai-Tibetan Plateau separated the eastern and western Tethyan area may contribute significantly to the disjunct distributions of Theligonum, and the North Atlantic migration appears to be the most likely pathway of expansion of Kelloggia to North America. Our results highlight the importance role of the QTP uplift together with corresponding geological and climatic events in shaping biodiversity and biogeographic distribution in the Northern Hemisphere.
为了评估青藏高原隆升在塑造北半球洲际间断中的作用，我们分析了两个草本残遗属，即忍冬属和金露梅属（忍冬科）在地质时间尺度内的起源和多样化。利用 5 个叶绿体标记，采用简约法、贝叶斯法和最大似然法推断了忍冬属和金露梅属内部以及它们之间的亲缘关系。利用贝叶斯松弛分子钟和祖先区重建法重建了这些类群的迁移路线和进化。研究结果表明，每个忍冬属和金露梅属都是单系的。金露梅属的东亚和北美物种约在 18.52 万年前分化，地中海地区的忍冬属与东亚类群约在 13.73 万年前分化。忍冬属和金露梅属均为特提斯植物区系残遗种，其祖先可能起源于特提斯海岸温暖的热带至亚热带环境。青藏高原的隆升可能显著促进了忍冬属的间断分布，北大西洋的迁移可能是金露梅属向北美扩张的最可能途径。研究结果突出了青藏高原隆升以及相应的地质和气候事件在塑造北半球生物多样性和生物地理分布方面的重要作用。
