You shed DNA everywhere you go – trace samples in the water, sand and air are enough to identify...

Human DNA can be sequenced from small amounts of water, sand and air in the environment to potentially extract identifiable information like genetic lineage, gender, and health risks, according to our new research.

Every cell of the body contains DNA. Because each person has a unique genetic code, DNA can be used to identify individual people. Typically, medical practitioners and researchers obtain human DNA through direct sampling, such as blood tests, swabs or biopsies. However, all living things, including animals, plants and microbes, constantly shed DNA. The water, soil and even the air contain microscopic particles of biological material from living organisms. Our team suspected that the sand and water samples we were using to study sea turtles would also contain DNA from a number of other species – including, of course, humans. What we didn’t know was just how informative the human DNA we could extract would be.

Two people on a boat collecting water samples from a river
The researchers were able to collect intact human DNA in water samples from a river in Florida. Todd Osborne, CC BY-ND
To figure this out, we took samples from a variety of locations in Florida, including the ocean and rivers in urban and rural areas, sand from isolated beaches and a remote island never usually visited by people. We found human DNA in all of those locations except the remote island, and these samples were high quality enough for analysis and sequencing. Our team suspected that the sand and water samples we were using to study sea turtles would also contain DNA from a number of other species – including, of course, humans. What we didn’t know was just how informative the human DNA we could extract would be.
The researchers were able to collect intact human DNA in water samples from a river in Florida. To figure this out, we took samples from a variety of locations in Florida, including the ocean and rivers in urban and rural areas, sand from isolated beaches and a remote island never usually visited by people. We found human DNA in all of those locations except the remote island, and these samples were high quality enough for analysis and sequencing.