title: Temporal variability is a personalized feature of the human microbiome.
abstract: BACKGROUND
  It is now apparent that the complex microbial communities found on and in the human body vary across individuals. What has largely been missing from previous studies is an understanding of how these communities vary over time within individuals. To the extent to which it has been considered, it is often assumed that temporal variability is negligible for healthy adults. Here we address this gap in understanding by profiling the forehead, gut (fecal), palm, and tongue microbial communities in 85 adults, weekly over 3 months.
  
  
  RESULTS
  We found that skin (forehead and palm) varied most in the number of taxa present, whereas gut and tongue communities varied more in the relative abundances of taxa. Within each body habitat, there was a wide range of temporal variability across the study population, with some individuals harboring more variable communities than others. The best predictor of these differences in variability across individuals was microbial diversity; individuals with more diverse gut or tongue communities were more stable in composition than individuals with less diverse communities.
  
  
  CONCLUSIONS
  Longitudinal sampling of a relatively large number of individuals allowed us to observe high levels of temporal variability in both diversity and community structure in all body habitats studied. These findings suggest that temporal dynamics may need to be considered when attempting to link changes in microbiome structure to changes in health status. Furthermore, our findings show that, not only is the composition of an individual's microbiome highly personalized, but their degree of temporal variability is also a personalized feature.
authors.forename: Gilberto E
authors.initials: GE
authors.lastname: Flores
authors.forename: J Gregory
authors.initials: JG
authors.lastname: Caporaso
authors.forename: Jessica B
authors.initials: JB
authors.lastname: Henley
authors.forename: Jai Ram
authors.initials: JR
authors.lastname: Rideout
authors.forename: Daniel
authors.initials: D
authors.lastname: Domogala
authors.forename: John
authors.initials: J
authors.lastname: Chase
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Leff
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Vázquez-Baeza
authors.forename: Antonio
authors.initials: A
authors.lastname: Gonzalez
authors.forename: Rob
authors.initials: R
authors.lastname: Knight
authors.forename: Robert R
authors.initials: RR
authors.lastname: Dunn
authors.forename: Noah
authors.initials: N
authors.lastname: Fierer
mesh_terms: D000328:Adult; D001419:Bacteria / Q000145:classification* / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology*; D005260:Female; D005546:Forehead / Q000382:microbiology*; D016680:Genome, Bacterial; D023281:Genomics / Q000379:methods; D006225:Hand / Q000382:microbiology*; D064368:Healthy Volunteers; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D064307:Microbiota; D008875:Middle Aged; D010802:Phylogeny; D014059:Tongue / Q000382:microbiology*; D055815:Young Adult