Fig. 4.

Relationships between summer and winter air samples (maroon and blue, respectively) and samples collected from a variety of possible source environments, including soils, leaf surfaces and various animal fecal samples. Communities were clustered using principal-coordinate analysis of the unweighted UniFrac distance matrix from a combined sequence data set of approximately 630,000 sequences. (A) Midwestern air samples alongside all three potential source environments (soil, leaf surfaces, and feces). (Inset) The same principal-coordinate analysis plot rotated along the first and third principal-coordinate axes. (B) Phylogenetic similarity between midwestern airborne bacterial communities and the communities of various fecal samples, including dog feces.