Excerpt:

MANY things make us stand out as individuals, from our fingerprints to our iris patterns. Now scientists have discovered another – the viruses in our gut.

People who are closely related tend to have similar bacteria in their intestines. But a study of the viruses in people’s faeces has found that even identical twins have uniquely different populations of these tiny tenants.

Florent Angly, a biologist at the University of Queensland and a co-author of the study, said the findings showed that factors such as health and diet were the biggest influence on the kinds of viruses people harboured.

”Twins have an identical genome, so including twins in the study was designed to find out what is more important: nature or nurture,” he said.