Although composition and functional potential of the human gut microbiota evolve over lifespan, kinship has been identified as a key covariate of microbial community diversification. To date, sharing of microbiota features within families has however mostly been assessed between parents and their direct offspring. Here, we investigate potential transmission and persistence of familial microbiome patterns and microbial genotypes in a family cohort (N=102) spanning three to five generations over the same female bloodline. We observe microbiome community composition to be associated with kinship, with seven (low-abundant) genera displaying familial distribution patterns. While kinship and current cohabitation emerged as closely entangled variables, our explorative analyses of microbial genotype distribution and transmission estimates point at the latter as a key covariate of strain dissemination. Highest potential transmission rates are estimated between sisters and mother-daughter pairs, decreasing with increasing daughter’s age, and being higher among cohabiting pairs than those ... (Show More)

Although composition and functional potential of the human gut microbiota evolve over lifespan, kinship has been identified as a key covariate of microbial community diversification. To date, sharing of microbiota features within families has however mostly been assessed between parents and their direct offspring. Here, we investigate potential transmission and persistence of familial microbiome patterns and microbial genotypes in a family cohort (N=102) spanning three to five generations over the same female bloodline. We observe microbiome community composition to be associated with kinship, with seven (low-abundant) genera displaying familial distribution patterns. While kinship and current cohabitation emerged as closely entangled variables, our explorative analyses of microbial genotype distribution and transmission estimates point at the latter as a key covariate of strain dissemination. Highest potential transmission rates are estimated between sisters and mother-daughter pairs, decreasing with increasing daughter’s age, and being higher among cohabiting pairs than those living apart. Although rare, we do detect potential transmission events spanning three and four generations, primarily involving species of the genera Alistipes and Bacteroides. Overall, while our analyses confirm the existence of family-bound microbiome community profiles, transmission or co-acquisition of bacterial strains appears to be strongly linked to cohabitation.

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