Fig. 4.

Comparative analysis of milk microbiomes versus mammalian gut (24) and skin (21) microbiomes. (A) Relative influence of assembly mechanisms shaping mammalian milk, gut, and skin microbiomes. We used null model analysis to compare phylogenetic beta diversity distances from each bacterial community to random phylogenetic trees (33, 34). Comparison calculations indicated how community assembly processes influenced microbial variation. (B) Milk microbiomes had the lowest microbial diversity, which may partially explain high ecological stochasticity in milk microbiomes, while skin and gut microbiomes did not differ from one another. *** indicates p < 0.001 from pairwise Wilcoxon rank sum test.