Association of log₂(PTR)s with disease status (A), relative abundances (B), and metabolomics (C). (A) log₂(PTR)s can be used to associate species with disease status. Significance was assessed by a fitting a linear model to log₂(PTR) per species and correcting for false-discoveries (q-values denote false-discovery rate). PTRs can be combined with relative abundances to assess species interactions (B) or the impact of metabolites (C).