Phylogenetic relationships in the mushroom genus Coprinus and dark-spored allies based on sequence data from the nuclear gene coding for the large ribosomal subunit RNA: Divergent domains, outgroups, and monophyly

Phylogenetic relationships were investigated in the mushroom genus Coprinus based on sequence data from the nuclear encoded large-subunit rDNA gene. F orty-seven species of Coprinus and 19 additional species from the families Coprinaceae, Strophariaceae, Bolbitiaceae, Agaricaceae, Podaxaceae, and Mon tagneaceae were studied. A total of 1360 sites was sequenced across seven d ivergent domains and intervening sequences, A total of 302 phylogenetically informative characters was found, Ninety-eight percent of the average dive rgence between taxa was located within the divergent domains, with domains D2 and D8 being most divergent and domains D7 and D10 the least divergent. An empirical test of phylogenetic signal among divergent domains also showe d that domains D2 and D3 had the lowest levels of homoplasy. Two equally mo st parsimonious trees were resolved using Wagner parsimony. A character-sta te weighted analysis produced 12 equally most parsimonious trees similar to those generated by Wagner parsimony. Phylogenetic analyses employing topol ogical constraints suggest that none of the major taxonomic systems propose d for subgeneric classification is able to completely reflect phylogenetic relationships in Coprinus. A strict consensus integration of the two Wagner trees demonstrates the problematic nature of choosing outgroups within dar k-spored mushrooms. The genus Coprinus is found to be polyphyletic and is s eparated into three distinct clades, Most Coprinus taxa belong to the first two clades, which together form a larger monophyletic group with Lacrymari a and Psathyrella in basal positions. A third clade contains members of Cop rinus section Comati as well as the genus Leucocoprinus, Podaxis pistillari s, Montagnea arenaria, and Agaricus pocillator. This third clade is separat ed from the other species of Coprinus by members of the families Stropharia ceae and Bolbitiaceae and the genus Panaeolus. (C) 1999 Academic Press.