Evolutionary genetics and systematics of fungi in the Collybia dryophila group

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dc.contributor.authorVilgalys, Rytas J.en
dc.contributor.committeechairMiller, Orson K.en
dc.contributor.committeememberFalkinham, Joseph O. IIIen
dc.contributor.committeememberHilu, Khidiren
dc.contributor.committeememberStipes, R. Jayen
dc.contributor.committeememberTurner, B.J.en
dc.contributor.committeememberWallace, Bruceen
dc.contributor.departmentBotanyen
dc.date.accessioned2014-08-13T14:38:52Zen
dc.date.available2014-08-13T14:38:52Zen
dc.date.issued1985en
dc.description.abstractI have undertaken an evolutionary and systematic study of fungi in the <i>Collybia dryophila</i> group (Basidiomycetes: Tricholomataceae). Species in the <i>C. dryophila</i> group occur worldwide as primary litter decomposers, yet little is known about their systematics. In a previous study, the <i>C. dryophila</i> group in North America was shown to consist of four biological species, identifiable on the basis of mating compatibility and certain taxonomic features (Vilgalys, 1983). In this study, crosses made using isolates from over 80 individuals of the <i>C. dryophila</i> group from Europe indicate that there are four species from that continent as well. All four species are rigorously intersterile, while intra-specific matings occur freely. One exceptional case of reduced intra-group mating compatibility is reported, which may be the result of divergence due to geographic isolation. Morphological studies indicate the four European biological species are all characterized by a high level of polymorphism, frequently involving features previously used to distinguish taxa. Because of this, diagnostic taxonomic features of the European species were reevaluated, and a revised taxonomy presented. Representative tester strains from North America, Europe, Asia, and Australia were crossed to determine world-wide mating relationships in the <i>C. dryophila</i> group. Six major compatibility groups are identified on the basis of frequent mating compatibility. In several instances, populations of different geographic origin are mating-compatible, suggesting that these allopatric populations might be conspecific. Intercompatible allopatric populations are not always similar in their fruit body morphology, however, suggesting that extensive geographic differentiation has occurred in the <i>C. dryophila</i> group. Genetic similarity of different populations was measured by the method of DNA hybridization. In general, there was good correspondence between mating compatibility and base sequence homology in the <i>C. dryophila</i> group. Allopatric, intercompatible populations, however, showed reduced homology when compared to that observed within sympatric populations. This suggests that geographic isolation may play a primary role in the evolution of different species in the <i>C. dryophila</i> group. Finally, a phylogeny based on DNA hybridization data is presented. In summary, several lines of evidence suggest an allopatric mode for speciation in the <i>C. dryophila</i> group.en
dc.description.adminincomplete_metadataen
dc.description.degreePh. D.en
dc.format.extentx, 118 leavesen
dc.format.mimetypeapplication/pdfen
dc.identifier.urihttp://hdl.handle.net/10919/49952en
dc.publisherVirginia Polytechnic Institute and State Universityen
dc.relation.isformatofOCLC# 13737609en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1985.V543en
dc.subject.lcshCollybia -- Morphologyen
dc.subject.lcshCollybia -- Geneticsen
dc.subject.lcshCollybia -- Evolutionen
dc.subject.lcshCollybia -- Reproductionen
dc.titleEvolutionary genetics and systematics of fungi in the Collybia dryophila groupen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineBotanyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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