'There are 10 times more bacterial cells in our bodies from the microbiome than human cells.
Viral DNA is known to integrate in the human genome, but the integration of bacterial DNA has not been described.
Using publicly available sequence data from the human genome project, the 1000 Genomes Project, and The Cancer Genome Atlas (TCGA), we examined bacterial DNA integration into the human somatic genome.
Here we present evidence that bacterial DNA integrates into the human somatic genome through an RNA intermediate, and that such integrations are detected more frequently in (a) tumors than normal samples, (b) RNA than DNA samples, and (c) the mitochondrial genome than the nuclear genome.'