From bubonic plague to mozzarella cheese, subway germs and bacteria represent an urban ecosystem
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If you've ever ridden on public transportation, you know how grimy it can get-dripping umbrella water, food wrappers, gum stuck under a seat, and that's not even taking into account the things you can't see. Scientists from Weill Cornell Medical College wanted to find out exactly what was lurking on New York City's subways, so they spent 18 months gathering DNA samples throughout NYC subway stations (a dream job, right?). The results of the study were, well, gross.

The researchers identified 637 known bacterial, viral, fungal and animal species, but almost half of all DNA collected were unidentifiable and did not match any organism known to the National Center for Biotechnology Information or the Centers for Disease Control and Prevention. Researchers think they are likely harmless-and may even be helpful, since they've been able to survive among more dangerous bacteria-but more research will be needed to determine what they are exactly.

This is the first genetic profile of a mass transit system and could have larger implications for public health. Continued sampling and testing could help to track disease outbreaks (like measles and Ebola) and reduce threats of bioterrorism. And this study has helped scientists determine what "normal" levels of pathogens are for urban environments. Surprisingly, those levels are fairly low. Only about 12 percent of the bacteria found are associated with disease. (Although the 215 species of bacteria they found that cause food poisoning and real, live bubonic plague still freak us out.)

The study also revealed some more fun facts about New Yorkers. Pizza and falafel are clearly an important part of the NYC diet-scientists detected DNA from bacteria associated with the production of mozzarella cheese at 151 stations and DNA from chickpeas on many subway platforms and benches. Whew-turns out-you're much more likely to walk away with hummus germs than Ebola (or even the flu!) after riding the subway. (Your cell is probably grosser than a public bus. Find out Why Your Phone Is Teeming With Germs.)