Genera within the Porphyromonadaceae, Veillonellaceae and Lachnospiraceae families are differentially abundant across microbial communities between the upper and lower digestive tract. These three families were detected among all ten digestive body habitats, but genera within them showed varying patterns of niche specialization to sites along the digestive tract. All genera with at least 0.001% abundance in at least one body site are reported here. Clades showing a statistically significant difference (by LEfSe) specifically between oral and stool samples are indiocated with asterisks. Abundances are reported on a log scale as averages. The scale bar shows the color-coding of the average relative abundance expressed as percentage, from low (black) to high (red). The Porphyromonadaceae family is interesting in that its average abundances are higher in the gut than in the oral body habitats, but specific genera within the family diverge: Tannerella and Porphyromonas are predominantly present in the oral cavity, whereas Parabacteroides, Barnesiella, Odoribacter and Butyricimonas show higher relative abundances in the gut. BM, buccal mucosa; KG, keratinized gingiva; HP, hard palate; Th, throat; PT, palatine tonsils; TD, tongue dorsum; Sal, saliva; SupP, supraginval; SubP, subgingival plaques.