Increasingly we see that the rich diversity of microbes and other species present in our environment influence human health and disease, especially in cities. In a newly published study, genetic sequencing was used to identify the microbes on surfaces across the entire New York City (NYC) subway system, the Gowanus Canal, and public parks. Nearly half of the DNA (48%) did not match any known organism. Identified organisms included 1,688 bacterial, viral, archaeal, and eukaryotic taxa. Almost half of the DNA found on the system’s surfaces did not match any known organism and just 0.2 percent matched the human genome. It was found that bacterial signatures can reveal a station’s history, such as marine-associated bacteria in a hurricane-flooded station. In some cases, the DNA found in some subway stations tended to match the neighborhood’s demographic profile. An area with a high concentration of Hispanic residents, for example, yielded a large amount of Hispanic and Asian genes. In another area, the DNA frequently read as British, Tuscan, and Finnish, groups not generally associated with the particular area. Dr. Mason, one of the authors, had an explanation for the finding: Scientists have not yet compiled a reliable database of Irish genes, so the many people of Irish descent who live in the area could be the source of DNA known to be shared with other European groups. Some evidence of pathogens was found (Bacillus anthracis), but a lack of reported cases in NYC suggests that the pathogens represent a normal, urban microbiome.
The report in the NY Times can be found at http://www.nytimes.com/2015/02/06/nyregion/among-the-new-york-city-subways-millions-of-riders-a-study-finds-many-mystery-microbes.html?_r=0. The report also contains a hyperlink to the full paper