Orders and Families of Ascosporogenous Yeasts and Yeast-Like Taxa Compared from Ribosomal RNA Sequence Similarities

Abstract

Extent of divergence in partial nucleotide sequences from large and small subunit ribosomal RNAs was used to assess the placement of genera among families and orders of ascosporogenous yeasts and yeast-like fungi. These data indicate the taxa comprise two orders: the Schizosaccharomycetales (genus Schizosaccharomyces) and the Saccharomycetales (Endomycetales; all genera of yeasts and yeast-like fungi except the fission yeasts). The data also suggest that certain currently accepted families are artificial. Furthermore, the rRNA sequence comparisons indicate that the ascosporogenous yeasts are not reduced forms of extant filamentous fungi.