A Candida albicans dispersed, repeated gene family and its epidemiologic applications

Candida albicans causes a wide variety of infections but can readily be isolated from the skin and mucosa of healthy individuals. To enable high-resolution epidemiologic studies on this common pathogen, a species-specific DNA probe has been isolated from its genome. There are approximately equal to 10 copies of the sequence dispersed among the chromosome-sized DNA molecules resolved by pulsed-field electrophoresis. New DNA polymorphisms in this gene family arise at high rates. As a consequence, this probe will readily distinguish strains from different patients in the same hospital and from various sites in individual patients. The DNA polymorphisms detected by using this probe are largely due to internal changes in members of the family rather than movement to new genomic locations. This suggests recombination or gene conversion rather than transposition as the mechanism producing the observed variation.