Composition of the gut microbiome in the ten subjects studied. Bacterial taxonomic assignments are indicated to the right of the heat map at the Phylum and Genus level except in cases where small numbers were detected (e. g. Proteobacteria), in which case taxa are summarized at higher levels. The relative abundance of each bacterial group is color coded as indicated by the key on the left (the number beside each colored tile indicates the lower bound for the indicated interval). Two samples were compared for each stool specimen, sampled on cm a part but otherwise worked up identically (conditions 1 and 2 in Table 2). The numbers of reads for the two samples from each subject were compared for significant differences using Fisher's exact test. The * indicates P < 0.05. Note that because each sequence read is treated as an individual measurement, the sample size is very large, with the result that many taxa with only modest differences nevertheless achieve significance.