Scientists can tell where you have been from your shoes

Every city in the world has its own mix of bacteria, scientists have found. This microbial “fingerprint” is so distinctive that the DNA in your shoe is quite likely to identify where you were recently, they say.

For this study, the researchers collected thousands of samples from public transport in 60 cities around the world. In doing so, they used the same contact points such as turnstiles and handrails in crowded subways and bus stations. More than 4,700 samples were analyzed with specialized equipment, so that even the genetic building blocks of the bacteria found became visible.

The main result is that no two cities are the same. Each metropolis studied so far – unfortunately no Dutch or Belgian city among them – has a unique molecular footprint of microorganisms.

The three-year scan also revealed thousands of species of unidentified microorganisms, including nearly 11,000 viruses and more than 1,300 species of bacteria that did not match any known species. The whole investigation was carried out for crown. The team, made up of a consortium of dozens of scientists from more than 60 research organizations, eventually collected the samples in 32 countries on six continents.

Research is also interesting for the police. Based on a person’s shoes, it is possible to determine which city they recently walked to.