Dissertation Research: Phylogeny in the Genus Omphalina (Basidiomycota Agaricales) and the Evolutionary Consequences of Mutualism

9321828 Vilgalys有人认为，远亲生物之间的互利关系可以导致新门的开始，并可能有助于植物在陆地上的殖民。 支持这些假设的论据的高度投机性的内容引起了很大的争议。 本计画将透过研究一群担子菌、脐螺属及其近缘种，以实证研究互惠共生的演化角色。 这一群体非常适合互利共生的进化研究，因为它包括密切相关的共生（即非互利）和互利共生物种（与藻类结合形成地衣），这表明向互利共生状态的转变可能是相对较近的（Lutzoni和Vilgalys，1993）。在本研究中，形态学和分子生物学特征将被用来推断脐螺属的物种之间的亲缘关系，以及研究该属与其他类群的关系。 这些第一批结果将被用来测试假设参与改变到一个互惠/地衣形成的生活方式的功能。 这个模型系统将解决有关不同生物体（在这种情况下，真菌与藻类形成地衣）可能互利共生的重要问题，从而产生新的生命形式。

9321828 Vilgalys It has been suggested that mutualistic associations between distantly related organisms can lead to the beginning of new phyla and may have been instrumental in the colonization of land by plants. The highly speculative content of the arguments supporting these hypotheses has led to much controversy. This project will undertake empirical studies of the evolutionary role of mutualism by studying a group of basidiomycete fungi, species in the genus Omphalina and its relatives. This group is well suited for evolutionary studies of mutualistic associations because it includes closely related saprophytic (i.e. non-mutualistic) and mutualistic species (those associating with algae to form lichens), suggesting that the transition to a mutualistic state might be relatively recent (Lutzoni and Vilgalys, 1993). In this study, both morphological and molecular characters will be utilized to infer the phylogeny or relationships of species of Omphalina to each other, as well as investigating the relationships of this genus to other groups. These first results will be utilized to test hypotheses concerning features involved in changing to a mutualistic/lichen forming life style. %%% This model system will address important questions concerning the possible mutualistic association of different organisms (in this case, fungi with algae to form lichens) leading to new life forms.