The fungi of the Candida genus, known to millions of patients worldwide for their ability to cause serious infections, were once all thought to be asexual. Even after scientists discovered that the mating habits ofCandida albicans were many and varied, they remained convinced that many of the more infectious ones did not mate. Now with the first report that Candida tropicalis can mate sexually as well, the chastity of the whole genus comes into further doubt.
“I think the really asexual fungi are going to turn out to be the exception, rather than the rule,” said Richard Bennett, assistant professor of biology at Brown University and senior author of the report published in theProceedings of the National Academy of Sciences.
The revelation that C. tropicalis mates sexually is not simply prurient. Some scientists, including Bennett, hypothesize that the pathogen’s mix of sexual behaviors may have evolved as a survival tactic. When things are going well, it may be best to reproduce asexually to keep a successful genome fairly stable. If conditions become hostile, then it makes sense to switch to sexual reproduction to accelerate the creation and proliferation of new, adaptive traits.