Fig. 1

a Sampling of nine samples from each subject following the protocols used by HMP. b Shannon’s index by smoking status and sample sites. The Shannon index did not significantly differ by smoking status in any sample sites. c Within- and between-group (smoker, nonsmoker) weighted UniFrac distance (beta diversity). Within- versus between-group differences were not statistically significant by permutational multivariate analysis of variance (adonis). In Figure b and c, the boxes are interquartile range (IQR); median values are the bands within the boxes; the lines outside the boxes are 1.5-times IQR; dots are outliers. d Mean and 95% interval of genus-relative abundance. Streptococcus was most abundant in all sites, but no genus was significantly different in relative abundance by smoking status according to the Wilcoxon rank-sum test with Bonferroni correction. Only the five most abundant genera are shown