Relative abundance of bacterial taxa throughout the gastrointestinal tract of RYGB, SHAM, and WMS mice. (A) Spatial effects of gastric bypass. The first principal coordinate from an unweighted UniFrac-based analysis is shown for luminal and mucosal samples taken from the stomach, small intestine, cecum, and colon. Values represent means ± SEM. DS, distal stomach; GP, gastric pouch; BP, biliopancreatic limb. (B) The dominant bacterial orders are shown for samples from the stomach, small intestine, cecum, and colon. Mean values are shown for samples isolated from the lumen (blue squares) and mucosa (red squares).