Scientists have identified more than 140,000 viruses in the human intestine, many of which were previously unknown. This is reported by Science Alert.
Researchers have compiled a new catalog of viruses, called the Gut Phage Database (GPD), based on the results of the analysis of more than 28 thousand metagenomes – collections of DNA sequences obtained by sequencing the gut microbiome. Microbiome samples were isolated from people from 28 countries.
A total of 142,809 viruses were identified, belonging to bacteriophages and infecting bacteria and archaea. Some of them belong to the Gubaphage clade, which seems to be the second most common in the human intestine after the crAssphage group. Previously, Gubaphage was thought to belong to the crAssphage-like virus family.
The detected viruses are not pathogens and are part of the normal ecosystem of the human intestine. They play the role of vectors for the horizontal transfer of bacterial genes, that is, the transport of DNA from bacteria to bacteria. Bacteriophages can encode genes that perform auxiliary functions for microorganisms, and contribute to coevolution, that is, the joint development of bacteria.
More than 36 percent of the identified viral groups infect more than one species of bacteria, which confirms their participation in creating a network of gene flow between different microorganisms.