Biological dark matter in our nose

When a group analyzed the genomic information in human nasal swab by a deep sequencer, they discovered diverse kinds of genomic information derived from human, bacteria and viruses. Interestingly, the twenty percent of this information didn't match with any known sequence in our planet. Accordingly, scientists call this twenty percent information "biological dark matter". It is considered that novel creatures which are different from known bacteria and viruses lurk behind this twenty percent information.