Phylogeny of the genus Agaricus inferred from restriction analysis of enzymatically amplified ribosomal DNA

The 26S and 5S ribosomal RNA genes and the intergenic region between the 26S and the 5S rRNA genes of the ribosomal DNA repeat of 21 species of Agaricus were amplified using PCR and then digested with 10 restriction enzymes. Restriction fragment length polymorphisms were found among the 21 putative species of Agaricus investigated and used to develop a phylogenetic tree of the evolutionary history of A. bisporus. The 5' end of the 26S gene showed move variability than the 3' end, A. excellens, A. chionodermus, and A. caroli represented the species most distantly related to A. bisporus. We present here the first comprehensive attempt at systematically resolving the entire genus Agaricus using modern techniques for molecular genetic analysis. Our data indicate that previous taxonomic schemes, based on morphological characters, are in need of revision. (C) 1996 Academic Press.