Figure 2.

Heat map showing the relationship between T₀ sample UNIFRAC clustering and OTU prevalence. The tree on the left side of the figure depicts the unsupervised hierarchical clustering of the 80 T₀ samples using the average linkage of unweighted UniFrac distances. The two main UniFrac clusters correspond to meat versus seafood products and the sub-branches are the 10 samples of each type of food product. The tree at the top of the figure depicts the unsupervised hierarchical clustering of the 508 OTUs in the T₀ data set using the average linkage of the correlation distances calculated from the OTU prevalence values. The approximately unbiased P-values were calculated using multiscale bootstrap resampling in PVCLUST and are given for each OTU prevalence cluster (boxes on the heat map). The identities of these OTU clusters are provided at the bottom of the tree; the identities of the core community clusters are identified at the bottom of the figure. A complete list of the OTUs, organized according to prevalence clusters and taxonomic assignment, can also be found in Supplementary File S4.