Fig. 5.

PCoA of the samples using sequences from each region. Samples are feces (blue), freshwater creek (bright green), freshwater lake (red), ocean (cyan), sediment (pink), skin (yellow), soil (dark green), and tongue (dark red). In the Procrustes analysis, using all reads, the samples derived from the 5′ end and the 3′ end are linked with a bar: in every case, the distance between the 5′ and 3′ reads of the same samples is much smaller than the distance between samples, highlighting the robustness of UniFrac analysis relative to the taxonomic analysis shown in Fig. 2. The smaller panels, using only 2,000 randomly chosen sequences per sample, show the weighted and unweighted UniFrac results from the 5′ and 3′ reads individually: the pattern of samples is highly reproducible (note that the direction of each axis is arbitrary, only the relative position of the points matters rather than whether a particular sample appears to the left or the right of the plot). As seen in ref 17, axis 1 is host associated/free living and axis 3 is saline/nonsaline environment.