You are the germs you carry

People leave more than fingerprints when they touch stuff - they also deposit a tell-tale trail of germs that could help investigators solve crimes, US researchers report.

They have been able to map a unique bacterial genetic signature left by nine different people, and say this germ-filled DNA lasted though day-to-day temperature changes, humidity and sunlight.

"Each one of us leaves a unique trail of bugs behind as we travel through our daily lives," Noah Fierer, a researcher at the University of Colorado at Boulder who led the study, says in a statement.