FIGURE 1.

Example networks constructed from QIIME 16S data. Four sub-networks, i.e. node and edge sub-sets from the inferred networks, are shown. The tundra sub-network (A) is dominated by two mutually exclusive clusters consisting of Acidobacteria and Alphaproteobacteria, the first of which is anti-correlated and the second correlated to pH. Notable exceptions to this trend are the Chloracidobacteria (a class within the Acidobacteria, here highlighted with an orange circle) which are positively correlated to pH, and several Rhizobiales (Alphaproteobacteria) and Chromatiales (Gammaproteobacteria) members (gray circle), which are negatively correlated to pH. The gut sub-network (B) reproduces the Prevotella enterotype, including negative correlations of the Prevotellaceae to an Akkermansia and an Escherichia OTU as well as to several Bacteroides OTUs. The moist forest sub-network (C) displays the neighbors of higher-level Nitrospirae representatives, among them the Geobacteraceae, with which Nitrospirales members might cross-feed. The skin sub-network (D) shows the neighbors of a Streptococcus OTU that acts as a negative hub.