A virome is a collection of viruses found in a biological community, such as an ecosystem or an organism. Scientists studying viruses use gene sequencing methods to study the viruses in these communities and classify them. This is known as the study of metagenomics. Viruses are found in all kinds of environments globally. One example of a virome is the human virome, which is the community of viruses living in various human organs. Bacteriophages, a type of virus, are the most common type of virus in the biosphere and in humans, and are found in feces, saliva, blood, and more.
In the 2000s, virologist Forest Rohwer performed gene sequencing on samples of seawater, soil, and human tissue. The studies revealed that the gene diversity of viruses globally is massive and mostly unrecorded. More research in the 2010s showed that the gut virome of humans is of special interest in human medicine. Scientists sort nucleic acids from the other components of viruses, and then analyze them. The large number of different viruses on Earth makes completing the Earth’s virome difficult. As of November 2018, a large virus database held information on 760,000 individual viruses and virus parts.