Fig. 3
From: A spatial gradient of bacterial diversity in the human oral cavity shaped by salivary flow
Mucosal communities also vary along an anterior to posterior gradient. A trend surface analysis (TSA) on samples of the oral mucosa and supragingival surfaces of 3 additional individuals (101 taxa, 542 samples) captured 10.5% of the total variation in the data, with the first axis accounting for 49% of the explained variance. TSA Axis 1 scores (y axis) are plotted as a function of tooth number (x axis). Each panel represents a unique tooth aspect (buccal, lingual) and intra-oral habitat (alveolar mucosa, keratinized gingiva, supragingival plaque, or buccal mucosa). Each point corresponds to a community sample, and samples are colored according to tooth class (molar, incisor, other tooth class). Blue curves denote local regression (loess) fits with associated 95% confidence intervals shaded in gray. Molar communities tended toward more positive scores along axis 1 compared to incisor communities, which tended toward more negative scores along axis 1 compared to molars. The remaining tooth classes were structured in an ordered fashion between the molar and incisor poles. These data suggest that both supragingival and soft tissue communities vary along a gradient from the front to the back of the mouth
