SLC15A1 and colitis: To understand whether the abundance of certain bacteria could explain variations in the susceptibility to DSS-induced colitis in WT and PepT1−/− mice, we correlated the abundance of operational taxonomic units (OTUs), a measure of taxonomic clustering, to parameters of inflammation obtained from WT and PepT1−/− mice with DSS-induced colitis (Supplementary Fig. 8).