krauter_salivary_microbiome_part_5_of_6_study2

The human oral microbiome is formed early in development. Its composition is influenced by environmental factors including diet, substance use, oral health, and overall health and disease. The influence of human genes on the composition and stability of the oral microbiome is still poorly understood. To uncover genetic effects, we studied both environmental and genetic characteristics in the largest twin sample studied for the oral microbiome as well as in a large cohort of unrelated individuals. In a subsample of the Colorado Twin Registry we identify several significantly heritable features of the oral microbiome. We also show that heritability persists in twins even when their cohabitation changes. The heritability of these traits correlates with the cumulative genetic contributions of over half a million single nucleotide sequence variants measured in a different population of unrelated individuals. Comparison of same-sex and opposite sex cotwins showed no significant differences. Finally we show that two new loci on chromosomes 7 and 12 are associated with the most heritable traits. Use of a two-stage strategy provides a powerful method to refine complex phenotypes prior to genetic analyses and improves power to detect associations by eliminating the need for “P-hacking” and reducing the multiple testing error correction.