Taxonomic assignments found in subgingival plaque clustered by cognitive status. Counts for each OTU that was identified more than 150 times/sample were included in this analysis. The total height of the bar represents 100% of the assigned sequences after quality filtering, and the size of the colored regions represents proportional contributions of each phylotype shown. For clarity, only major families (>3%) are listed in the color key. OTU, Operational Taxonomic Units.