Fig. 1

Beta diversity comparisons between twin pairs: Beta diversity measurements for MZ(n = 366 pairs), DZ(n = 386 pairs, and unrelated individuals(n = 37,832 pairs). Mann-Whitney U two-tailed test was applied between groups (Bray-Curtis and Weighted UniFrac Beta Diversity Measurements shown). P-values were determined with 10,000 permutations of the group labels. a. Entire twin sample(n = 752 pairs) b. only twin pairs either 18 and younger or those over the age of 18 and living together(n = 588 pairs). (**) p-value < 0.0005, (*) p-value < 0.05)