Spatio-temporal evolution of Cedreleae (Cedrela, Toona) from Paleocene to Pleistocene

古新世至更新世雪松科（Cedrela、Toona）的时空演化

• 批准号: 65266953
• 负责人: Professorin Dr. Alexandra Nora Müllner-Riehl
• 金额: --
• 依托单位: Royal Botanic Gardens, Kew
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/65266953?language=en
• 关键词: Spatio; temporal; evolution; Cedreleae; Cedrela

Although Cedrela (Meliaceae) is one of the world´s economically most important and exploited timber genera, its taxonomic status is by no means satisfactory. By identifying boundaries between evolutionary species, it is possible to ask what features are associated with species boundaries, whether the multifarious aspects of species tend to evolve in concert, and what role the external environment plays in producing genetic and phenotypic clusters. A major aim of the proposed project is the investigation of the spatio-temporal evolution of the monophyletic tribe Cedreleae (New World Cedrela, Old World Toona) in the light of global climate change and tectonic history from Paleocene to Pliocene. Climate change during this period of time is known to have been a driving force for shaping spatial patterns of Meliaceae. The distribution range of Cedrela comprises Central and South America (New World), whereas Toona is distributed throughout India, Indo-China, Malesia, and Australasia (Old World). From Eocene to Miocene the two genera were both part of the tropical flora of the Northern Hemisphere, which is corroborated by a number of fossil findings in Eurasia and North America and in areas formerly linking the continents (North Atlantic land bridge, Beringia). For Cedrela, multiple fossil findings indicate southward migration from North America to Central America from the Miocene to Pliocene. We will employ multi-gene phylogenies for both genera on specific and infra-specific level, set in a temporal context by fossil calibrations or constraints. Together with information on the geographical and ecological attributes of species and knowledge about the geological history of the distributional areas, we want to answer the following questions: (1) At what time and in which setting did Cedreleae diverge into Cedrela and Toona?;(2) Was diversification in Cedrela associated with habitat niche requirements?;(3) Were widespread and variable lowland species distributed in rain forest and in drier areas derived from dry forest species of Cedrela with local ranges?;(4) Is similarity of ecological/climate preferences correlated with evolutionary relatedness of species in Cedrela? Results will be incorporated in a modern generic monograph of Cedrela (Pennington and Muellner, in preparation) and serve as source of information for setting up IUCN Red List assessments for species under threat. In addition, DNA data of Cedrela might act as barcodes for future identification of timber by official authorities.

虽然雪松属是世界上经济上最重要和最受开发的木材属之一，但其分类地位并不令人满意。通过识别进化物种之间的边界，我们可以问什么特征与物种边界相关，物种的多样性方面是否倾向于协同进化，以及外部环境在产生遗传和表型集群中扮演什么角色。拟议项目的一个主要目的是调查单系族Cedreleae（新世界Cedrela，旧世界香椿）的时空演变，从古新世到上新世的全球气候变化和构造历史。在这段时间内的气候变化是已知的已形成的空间格局楝科的驱动力。雪松属的分布范围包括中美洲和南美洲（新大陆），而红椿分布在整个印度，印度支那，马来西亚和澳大拉西亚（旧大陆）。从始新世到中新世，这两个属都是北方半球热带植物群的一部分，这一点被欧亚大陆和北美以及以前连接大陆的地区（北大西洋陆桥，白令海）的一些化石发现所证实。对于Cedrela，多个化石发现表明从中新世到上新世从北美向南迁移到中美洲。我们将采用多基因遗传学的属在特定和种下的水平，设置在一个时间的背景下，化石校准或约束。结合有关种的地理和生态特征以及分布区地质历史的知识，我们想回答以下问题：（1）雪松属在什么时候和什么环境中分化成雪松属和香椿属？(2)雪松属植物的多样性与生境生态位要求有关吗？(3)分布在雨林和干燥地区的广泛且可变的低地物种是否源于具有局部分布范围的雪松属干林物种？; (4)相似性的生态/气候偏好相关的物种在雪松的进化相关性？研究结果将被纳入Cedrela（彭宁顿和Muellner，正在编写中）的现代通用专著中，并作为建立IUCN红色名录评估受威胁物种的信息来源。此外，雪松的DNA数据可能作为官方当局未来识别木材的条形码。