Although Gly-MCA administration did not affect FXR signaling in the liver (Supplementary Figure S10a), it clearly diminished the beneficial effects of RYGB microbiota transfer on hepatic steatosis (Fig. 7g–h and Supplementary Figure S10b), without inherently affecting liver morphology (Supplementary Figure S9e, f). The gene discussed is NR1H4; the disease is fatty liver disease.