SEQUENCE-ANALYSIS OF THE INTERNAL TRANSCRIBED SPACER-2 (ITS2) FROM YEAST SPECIES WITHIN THE GENUS CANDIDA

Nucleotide sequences of the internal transcribed spacer 2 (ITS2) regio ns were determined for 13 species within the genus Candida, representi ng a collection of those species pathogenic for humans. No two species had identical sequences and the sizes of ITS2 varied fourfold, repres enting an apparent continuous gradient of nucleotides. When present, s equence homologies were observed in the 5' end of ITS2, and many speci es exhibited more limited homologies within three known conserved doma ins found in other yeasts. Cluster analysis of primary sequence reveal ed a concordance with a known taxonomic subfamily and suggests that ce rtain species within the genus form a similar grouping. A majority of species exhibited similar presumptive RNA secondary structures, consis tent with the hypothesis that these spacer regions are essential for c orrect processing of the 5.8S and 28S subunits.