Phylogeny and Evolution of the True Thistles, Genus Cirsium (Compositae-Cardueae)

真正的蓟属植物种类繁多，在分类学上有问题，在生态和经济上也是全世界北温带植物区系的重要组成部分。物种间最小的遗传差异阻碍了蓟属亲缘关系的解决，但现在可以通过识别三个高度可变的核基因区域来克服，这些区域提供了属内精细级别的系统发育信息。真正的蓟的系统发育将通过比较三个核基因区域(G3pdh、B1启动子和组氨酸激酶)的DNA序列来研究。有待检验的假设包括：(1)生态多样性的新大陆蓟是否构成一个自然群体？(2)新大陆物种(尤其是加州特有物种)是适应性辐射的好例子吗？(3)新大陆蓟起源于共同的欧洲或亚洲祖先吗？(4)蓟与近缘的Carduus属不同吗？蓟属内自然分组的分解也将被用来取代盛行的、非常不自然的、分段的分类。实现蓟的自然分类对于为未来对真正的蓟的基础和应用研究提供一个具有生物学意义的框架至关重要。这项研究将对丰富加州大学伯克利分校的本科教育产生更广泛的影响。本科生将被招募参与这些努力，并将参与实验室研究。该项目还将涉及高危、种族多样化的高中生，他们将被介绍给生物学研究，并将参与种植植物的研究。通过确定蓟属内的自然种群，这项研究将帮助生防研究人员选择新的药剂来控制非本地杂草蓟。将通过实地讲习班指导土地资源专业人员和普通公众保护稀有蓟，一个更大的小组将可以在杰普森在线交流网站上获得结果，从而获得关于现代系统方法对了解区域植物多样性和分类的重要性的信息。

The true thistles (genus Cirsium) are highly diverse, taxonomically problematic, and ecologically and economically important components of north temperate floras worldwide. Minimal genetic variation across species has hampered resolution of relationships in Cirsium but can now be overcome with the identification of three highly variable, nuclear gene regions that provide phylogenetic information at fine-scale levels within the genus. Phylogeny of the true thistles will be studied by comparing DNA sequences from three nuclear gene regions (G3pdh, the B1 promoter, and histidine kinase). Hypotheses to be tested include: (1) Do the ecologically diverse New World thistles constitute a natural group? (2) Are the New World species (especially the Californian endemics) good examples of adaptive radiation? (3) Did the New World thistles arise from a common European or Asian ancestor? (4) Is Cirsium distinct from the closely related genus Carduus? Resolution of natural groupings within Cirsium also will be used to replace the prevailing, highly unnatural, sectional classification of the genus. Achieving a natural classification of Cirsium is critically important to provide a biologically meaningful framework for future basic and applied research on true thistles. This research will have the broader impacts of enriching undergraduate education at the University of California, Berkeley. Undergraduate students will be enlisted in the efforts and will participate in laboratory research. The project will also involve at-risk, ethnically diverse high school students, who will be introduced to biological research and will participate in growing research plants. By defining natural species groups within Cirsium, this research will aid biological-control researchers in choosing new agents for controlling non-native weedy thistles. Land resource professionals and the lay public will be instructed in the conservation of rare thistles by means of a field workshop, and a larger group will have access to results on the Jepson Online Interchange website, thereby obtaining information on the importance of modern systematic approaches to understanding regional plant diversity and classification.