Genetic structure of typical and atypical populations of Candida albicans from Africa

Atypical isolates of the pathogenic yeast Candida albicans have been report ed with increasing frequency, To investigate the origin of a set of atypica l isolates and their relationship to typical isolates, we employed a combin ation of molecular phylogenetic and population genetic analyses using rDNA sequencing, PCR fingerprinting, and analysis of co-dominant DNA nucleotide polymorphisms to characterize the population structure of one typical and t wo atypical populations of C. albicans from Angola and Madagascar, The exte nt of clonality and recombination was assessed in each population. The anal yses revealed that the structure of all three populations of C, albicans wa s predominantly clonal but, as in previous studies, there was also evidence for recombination. Allele frequencies differed significantly between the t ypical and the atypical populations, suggesting very low levels of gene flo w between them. However, allele frequencies were quite similar in the two a typical C. albicans populations, suggesting that they are closely related, Phylogenetic analysis of partial sequences encoding the nuclear 26S rDNA de monstrated that all three populations belong to a single monophyletic group , which includes the type strain of C. albicans, (C) 1999 Academic Press.