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.
