In the profile, `ref_mOTU` represent species with a reference genome sequence in NCBI. While `meta_mOTU` and `ext_mOTU` represent species that have not been sequenced yet (they do not have a representative genome in NCBI).
the `unassigned` at the end of the file (check with `tail test_sample.motus`), represents species that we know to be present, but are not able to profile. The `unassigned` is useful to have a correct evaluation of the relative abundance of all species (more info [here](https://github.com/motu-tool/mOTUs_v2/wiki/Explain-the-resulting-profile#-1)).