http://www.livescience.com/10724-poop-unique-gut-viruses-person.htmlLike a fingerprint, the virus communities in the human gut are unique to each individual, a new study on poop DNA suggests. Even identical twins have very different collections of viruses colonizing their lower intestines. This is in contrast to bacterial communities, which are similar in related individuals, the researchers say. (While bacteria can live and reproduce on their own, viruses consist of genetic material packaged inside a capsule structure and can only reproduce inside a host.)
The study sheds light on the largely unexplored world of viruses living in the lower intestine. Most of these "friendly" viruses, which don't cause diseases, make their home inside bacteria already living in the gut. These viruses are thought to influence the activities of gut microbes, which among their other benefits, allow us to digest certain components of our diets, such as plant-based carbohydrates, that we can't digest on our own.
In recent years, a number of projects worldwide have been initiated to catalog the microbes that live in and on the human body, with the goal of understanding the relationship between microbial communities (including viruses and bacteria) and overall health and disease.
The new research, published this week in the journal Nature, suggests such projects should also focus on the viruses that co-exist and co-evolve with bacteria and other microbes that normally live in our bodies. For instance, these viruses might act as barometers for the overall health of the gut microbial community as it responds to challenges or recovers after an illness or therapeutic intervention.