Polistes dominulaWIKIMEDIA, HANS HILLEWAERTThe domestic yeast Saccharomyces cerevisiae, a model organism in genetic research, is surprisingly poorly understood outside the lab. In particular, researchers have struggled to explain genomic data suggesting that S. cerevisiae outcrosses regularly in the wild, given the apparent absence of natural environments favoring the species’ sexual reproduction. Researchers at the University of Florence have now identified at least one place where outcrossing is occurring regularly in the wild: within wasp guts. The team’s findings were published in PNAS today (January 18).
“Despite the evidence for frequent outcrossing, derived from the sequences of yeast genomes, no one knew before where outcrossing could take place,” said study coauthor Duccio Cavalieri, an associate professor of biology at the University of Florence.
Earlier work had shown that both pure and hybrid strains of S. cerevisiae could survive the guts of hibernating Polistes dominula wasps, and that these wasps played an important role in moving yeasts between grapes in European wineries. But it was unclear whether the hibernating wasps were simply incubating diverse yeast strains or if they were in fact promoting sexual reproduction and hybridization among gut-dwelling yeast.
To find out, Cavalieri’s team fed lab wasps five S. cerevisiae strains. The researchers then compared the proportion of outbred strains in ...
