We have used the CRISPR anti-phage immune system of bacteria to
analyze a large metagenomic data set of 124 individuals and provide
awide perspective on the bacteriophages resident in the human gut.
The large number of individuals sequenced to produce this data set
and the ability of CRISPR spacers to reliably identify phage genomes
across the analyzed population, including those not necessarily
highly active in feces at the time of sampling, have allowed us to
accumulate a significant, although not exhaustive, set of relevant
phages. We then used this set as a benchmark to examine the
question of phage sharing across individuals using various additional
data sets, which have only been looked at separately before.