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

9615542功能互补的远亲生命形式之间的卢佐尼共生关系提供了关键的创新，导致了主要生物体群体的起源和多样化。地衣共生是真菌和光合藻(通常是绿藻或蓝藻)之间相互作用的结果，使得至少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)；所有已知的子囊菌物种中有50%参与地衣共生。尽管互惠互利作为一种主要的进化力量具有无可争辩的重要性，但人们对互惠互利群体多样化的起源和途径知之甚少。显然，丝状子囊菌的系统发育和互惠共生(地衣化)对这一门的进化的影响只能通过地衣形成子囊菌的分类采样来理解，该分类采样至少与目前正在进行的非地衣形成子囊菌的采样相当。芝加哥菲尔德博物馆的Lutzoni博士正在开始对形成地衣的子囊菌进行分子系统发育分析，这是该项目的一部分。该项目的一个目标是发现形成地衣的真菌相对于未形成地衣的真菌的祖先和关系。为了实现这一目标，来自三个核基因的三个分子数据集将从大量地衣化子囊菌和非地衣化子囊菌的代表中收集，预计将显示信息性变异。将特别强调Gyalectales和Lichinales，这是地衣形成真菌的两个分类目，据信包括丝状子囊菌的早期辐射。还将探讨与从多个基因的DNA序列数据构建系统发育树有关的理论问题。

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.