May 27, 2009
Study finds yeast has full sexual cycle
U.S. scientists say an emerging form of the pathogenic yeast Candida can complete a full sexual cycle in a test tube, even while missing reproduction genes.
Humans are susceptible to three types of Candida infection: thrush (in the mouth and throat), vaginal infection and a sometimes fatal systemic infection of bloodstream and organs, such as the kidney.
Sex contributes to the Candida yeast species' evolutionary success, said Dr. Joseph Heitman, director of the Center for Microbial Pathogenesis at Duke University.
I think the fact it has a complete sex cycle is likely to play a role in the evolution of drug resistance in this emerging pathogenic yeast species.
In a paper published May 24 online in the journal Nature, Heitman's team reports eight Candida species have a sexual cycle missing many genes related to reproduction found in other species.
With co-author Anna Floyd, Heitman and Dr. Jennifer Reedy explored the question further in a study appearing in the May 14 issue of the journal Current Biology.
The most important finding was that yeast can
complete a full sexual cycle, i.e., reproduce, without the genes previously thought to be necessary for reproduction.
What we found is that the sexual cycle has a new way to create genetic diversity, and it provides a unique vantage point from which we can explore the mechanisms of sexual reproduction, Reedy said.