Abstract
Candida dubliniensis
is the closest known relative of
Candida albicans
, the most pathogenic yeast species in humans. However, despite both species sharing many phenotypic characteristics, including the ability to form true hyphae,
C. dubliniensis
is a significantly less virulent and less versatile pathogen. Therefore, to identify
C. albicans
-specific genes that may be responsible for an increased capacity to cause disease, we have sequenced the
C. dubliniensis
genome and compared it with the known
C. albicans
genome sequence. Although the two genome sequences are highly similar and synteny is conserved throughout, 168 species-specific genes are identified, including some encoding known hyphal-specific virulence factors, such as the aspartyl proteinases Sap4 and Sap5 and the proposed invasin Als3. Among the 115 pseudogenes confirmed in
C. dubliniensis
are orthologs of several filamentous growth regulator (FGR) genes that also have suspected roles in pathogenesis. However, the principal differences in genomic repertoire concern expansion of the
TLO
gene family of putative transcription factors and the IFA family of putative transmembrane proteins in
C. albicans
, which represent novel candidate virulence-associated factors. The results suggest that the recent evolutionary histories of
C. albicans
and
C. dubliniensis
are quite different. While gene families instrumental in pathogenesis have been elaborated in
C. albicans
,
C. dubliniensis
has lost genomic capacity and key pathogenic functions. This could explain why
C. albicans
is a more potent pathogen in humans than
C. dubliniensis
.