Consequences of Mutualism (Lichenization) on the Phylogeny and Diversification of Ascomycetes

小行星9615542 具有互补功能的远亲生命形式之间的共生关系提供了关键的创新，导致了主要生物群体的起源和多样化。地衣共生体是真菌和光合藻类（通常是绿色藻类或蓝细菌）之间的互利相互作用的结果，使至少20%的已命名真菌物种得以进化。大多数地衣包括自然界中的子囊菌（其他是担子菌）;所有已知的子囊菌中有50%参与地衣共生。尽管互利共生作为一种主要的进化力量具有无可争议的重要意义，但人们对互利共生群体之间多样化的起源和途径知之甚少。很明显，丝状子囊菌的共生和互利共生（地衣化）对这门的进化的影响，可以理解只有与地衣形成的子囊菌的分类学采样，至少是可比的采样目前正在进行的非地衣形成的子囊菌。作为这项事业的一部分，芝加哥菲尔德博物馆的Lutzoni博士正在开始对地衣形成的子囊菌进行分子系统发育分析。 该项目的一个目标是发现地衣形成真菌相对于非地衣化真菌的祖先和关系。为了实现这一目标，三个分子数据集，从三个核基因预计将显示信息的变化，将收集广泛的地衣化和非地衣化子囊菌的代表。特别强调的是，将直接对Gyalectales和地衣，地衣形成真菌的两个分类目被认为包括丝状子囊菌的早期辐射。从多个基因的DNA序列数据构建系统发育树有关的理论问题也将进行探讨。

9615542 Lutzoni Symbiotic associations between distantly related life forms that have complementary functions provided key innovations that led to the origin and diversification of major groups of organisms. Lichen symbioses, resulting from mutualistic interactions between fungi and photosynthetic algae (usually green algae or cyanobacteria), enabled the evolution of at least 20% of all named species of fungi. Most lichens include fungi that are ascomycetous in nature (the others are basidiomycetes); 50% of all known species of ascomycetes are involved in lichen symbioses. Despite the indisputable significance of mutualism as a major evolutionary force, very little is known about the origins and pathways of diversification among mutualistic groups. It is clear that the phylogeny of filamentous ascomycetes and the impact of mutualism (lichenization) on the evolution of this phylum can be understood only with taxonomic sampling of lichen-forming ascomycetes that is at least comparable to the sampling currently underway for non lichen-forming ascomycetes. Dr. Lutzoni at the Field Museum in Chicago is commencing molecular phylogenetic analyses of lichen-forming ascomycetes as part of this enterprise. One goal of the project is to discover the ancestry and relationships of lichen-forming fungi relative to their non-lichenized counterparts. To attain this goal, three molecular data sets, from three nuclear genes expected to show informative variation, will be gathered from representatives of a wide array of lichenized and non-lichenized ascomycetes. Special emphasis will be directed toward the Gyalectales and Lichinales, two taxonomic orders of lichen-forming fungi believed to comprise the early radiation of filamentous ascomycetes. Theoretical issues relating to constructing phylogenetic trees from DNA sequence data from multiple genes will also be explored.