Phylogenetic relationships of the basidiomycete family Polyporaceae will be investigated using DNA and amino acid sequence data. Sporocarps in the Polyporaceae range from simple, resupinate forms, to complex, pileate-stipitate forms. Hymenophores may be poroid, lamellate, toothed, etc. This study will inform the interpretation of fungal morphological evolution by providing a phylogenetic context. The principal focus is on: (a) the roles of morphological elaboration, reduction, and convergence in sporocarp evolution, (b) patterns of switching between hymenophore types. Evolution and homology of decay types and mating systems will be similarly elucidated. Sampling of diverse genera, with special attention on type species, will contrast traditional and modern concepts of the Polyporaceae. Two sources of molecular data will be utilized: mitochondrial small subunit ribosomal RNA genes and nuclear-encoded vacuolar ATPase B-subunits. Emphasizing cladistic methods, phylogenetic analyses of the two regions will permit independent corroboration of gene trees used to interpret organismal phylogenies. Results from unconstrained phylogenetic analyses will be compared with those obtained under user-defined topological constraints, enabling a quantitative evaluation of competing taxonomic and evolutionary hypotheses. %%% To date molecular phylogenetic studies of the fungi (with 1.5 million species, the most speciose taxon after the insects) have been quite limited, making this study an important one since a comprehensive phylogenetic classification for the group is presently lacking. Some preliminary data are available for the Polyporaceae, which are hymenomycetes (fungi that bear their spores on an exposed hymenium). Polypores and other wood decay fungi play a significant role in global carbon cycling and cause great losses in the timber industry. The information derived from this research will be of practical use in studies of wood biodegradation because it will clarify results of homology and function in wood rot organisms.
