title: Unveiling an abundant core microbiota in the human adult colon by a phylogroup-independent searching approach.
abstract: The potential presence of widespread and stable bacterial core phylogroups in the human colon has promoted considerable attention. Despite major efforts, no such phylogroups have yet been identified. Therefore, using a novel phylogroup- and tree-independent approach, we present a reanalysis of 1,114,722 V2 region and 71,550 near full-length 16S rRNA sequences from a total of 210 human beings, with widespread geographic origin, ethnic background and diet, in addition to a wide range of other mammals. We found two highly prevalent core phylogroups (cores 1 and 2), belonging to the clostridial family Lachnospiraceae. These core phylogroups showed a log-normal distribution among human individuals, while non-core phylogroups showed more skewed distributions towards individuals with low levels compared with the log-normal distribution. Molecular clock analyses suggest that core 2 co-evolved with the radiation of vertebrates, while core 1 co-evolved with the mammals. Taken together, the stability, prevalence and potential functionality support the fact that the identified core phylogroups are pivotal in maintaining gut homeostasis and health.
authors.affiliation: Nofima, The Norwegian Institute of Food, Fisheries and Aquaculture Research, Aas, Norway. monika.sekelja@nofima.no
authors.forename: Monika
authors.initials: M
authors.lastname: Sekelja
authors.forename: Ingunn
authors.initials: I
authors.lastname: Berget
authors.forename: Tormod
authors.initials: T
authors.lastname: Næs
authors.forename: Knut
authors.initials: K
authors.lastname: Rudi
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification* / Q000235:genetics*; D001483:Base Sequence; D003106:Colon / Q000382:microbiology*; D006094:Gram-Positive Bacteria / Q000145:classification / Q000235:genetics; D006801:Humans; D054892:Metagenome; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D012336:RNA, Ribosomal, 16S