Fig. 3

Possible OP microbiome transmission between cohabitants. A Distribution of genomic distances between genotypes in cohabitation and non-cohabitation pairs. Genomic distance was calculated using the Hamming distance, which measures the proportion of differing positions between two genotypes. The p value was calculated by Kolmogorov–Smirnov (K-S) test (two-sided). B Box plots showing the hamming distances between genotypes in cohabitation and non-cohabitation pairs across different species. P values were obtained using the Wilcoxon rank-sum test (two-sided). C Phylogenetic tree of genotypes of Prevotella sp. oral taxon 306 from different individuals. The color of the tip points represents different families, and close pairs from the same household are marked with triangles and connected by dotted lines, all of which were defined as strain transmission events in the following analysis. D Distribution of genomic synteny scores between genotypes in cohabitation and non-cohabitation pairs. The p value was calculated by Kolmogorov–Smirnov (K-S) test (two-sided). E Correlation between the transmission rate of species in OP samples and oral samples. F Box plots displaying the distance between genotypes in different relation types. P values were obtained using the Wilcoxon rank-sum test (two-sided). G Comparing the number of putative transmission events among different relation types. Odds ratios (OR) and p values were calculated using Fisher’s exact test (two-sided). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001