Tracing the impact of the Andean uplift - Evolution of St. John's wort (Hypericum L.) in South America: historical biogeography, character evolution, niche shifts and age estimations

不断变化的环境一直是进化的推动力。在南美山脉，自从安第斯山脉北部的科迪勒拉山脉在700万到1400万年前开始隆起以来，开花植物物种的多样性就一直在进化。几项研究表明，这些山地隆起对新热带植物区系的显著多样化产生了重大影响。金丝桃属（圣约翰草，金丝桃科）是安第斯山脉高海拔植被的重要成员。在这些高海拔的栖息地有超过25%的金丝桃物种，在安第斯山脉有一个主要的多样性中心。近年来对金丝桃属植物的系统发育研究证实其为单系类群。对嗜智金丝桃物种进化史的进一步了解受到样本可用性低和缺乏详细的实地观察的限制。基于新获得的样本，将进行嵌套的基于dna的系统发育分析。所得结果将对南美金丝桃属植物的生物地理学有更详细的认识。反过来，这将用于追踪生态变化和反复气候变化对该地区金丝桃内进化的影响。这项研究将有助于我们了解安第斯山脉生境的进化史以及全球范围内影响植物多样性的机制。

Changing environments have always been a driving force of evolution. In the South American mountain ranges, an extraordinary high diversity of flowering plant species has evolved since the northern Andean Cordilleras have started to uplift 7-14 million years (Ma) ago. Several studies have shown the major impact ofthese mountain uplifts in the outstanding diversification of the Neotropical flora. The medicinally interesting genus Hypericum (St. John's wort, Hypericaceae) is an important member ofthe Andean vegetation at higher altitudes. With more than 25% of its species in these high altitude habitats, Hypericum has a main center of diversity in the Andes. Recent phylogenetic studies in Hypericum verified the Nootropic species as a monophyletic group. Further insights into the evolutionary history of the Nootropic Hypericum species is limited by low sample availability and lack of detailed field observations. Based on the newly obtained samples a nested DNA-based phylogenetic analysis will be performed. The obtained results will give detailed insights into biogeography of South American Hypericum. This in turn, will be used to trace ecological shifts and the influence of repeated climate changes on evolution within Hypericum in this area. The investigation will significantly contribute to our understanding of the evolutionary history of habitats in the Andes in general and mechanisms influencing plant diversity on a global scale.