Metagenomic analysis of viruses in the fecal micorobiota of monozygotic twins and their mothers

The human gut contains our largest collection of viruses, which infect the bacteria, archaea, and small eukaryotes that comprise its microbiota. Viral diversity and lifecycles are poorly understood in this as well as other body habitats. Therefore, we sequenced the viromes (metagnomes) of virus-like particles (VLPs) isolated from fecal samples that were collected from 4 pairs of adult female monozygotic (MZ) twins and their mothers at three different time points over the course of a year. These datasets were compared to datasets of sequenced bacterial 16S rRNA gene amplicons and total fecal community DNA. While our previous metagenomic analyses demonstrated that co-twins and their mothers share a greater degree of similarity in their fecal bacterial communities than unrelated individuals1, the current study shows that viromes, which encode diverse metabolic functions, are unique to individuals regardless of family relationships. Moreover, viromes are dominated by temperate phage that exhibit remarkable stability over the one year study period. Together these results indicate that the virome is a highly individualistic component of our gut ecosystems, even among people with identical human genotypes.