(Translated by Claudia Alderman)
Recalling of the movie Jurassic Park, one wonders about the potential dangers of reviving an ancient pathological microbe that could produce a modern plague. "There exists the possibility," he says, but Carvajal thinks that these species have been living with man for thousands of years." Indeed, that suspicion proved to be true.
Simultaneously, on the other side of the globe two cases of bottled tea were found clouded with contamination in 2010. The manufacturer sent the bottles to Ching-Fu Lee at the National Hsinchu University of Education, one of the few yeast taxonomists in Taiwan. He identified the contaminant as a new species of Candida and began to write a paper describing his discovery. During the peer review process, the anonymous reviewer suggested that Lee check the National Institutes of Health GenBank database. There he found the genetic sequence of the new species of Candida that Carvajal had recovered from the ancient fermentation vessel. Lee immediately contacted Carvajal, along with the latter's collaborator Stephen James, a yeast taxonomist at the Institute of Food Research in England, and the three teams of scientists jointly published their paper in the February issue of the International Journal of Food Microbiology.
But how did the identical yeast turn up simultaneously in Taiwan and Quito? "I don't think this is a beverage-related yeast, I think it is a human-related yeast," Carvajal says. "We know now that there were contacts between Polynesians and South American peoples. [Polynesians] departed from Taiwan 6,000 years ago."
Carvajal cites the example of another new yeast he has discovered, C. fodens, to buttress his argument. The yeast was collected in Australia, Costa Rica and Ecuador's Galápagos Islands. Genetic analysis shows that the yeast from all three Pacific locations are identical. "It is very hard to imagine that such a distance was covered by one single strain," he says. "This yeast is tightly associated with the flowers of the sweet potatoes. This probably has some relation with human migration, because we know that sweet potatoes come from the Andes. We are using yeasts to track human migration and contacts. That is part of what we call 'microbiological archaeology.'"