GF mice show differences in crypt morphology in the proximal colon compared with the distal colon but resemble Wnt gene expression patterns of SPF mice. A: Crypt morphology in the proximal (79.08 ± 1.72 μm) versus the distal (152.10 ± 2.57 μm) colon of GF mice. B: Results of qPCR for Wnt signaling genes in GF mice were Wnt5a (difference, 4.65-fold), Wnt11 (difference, 2.82-fold), Fzd3 (difference, 49.51-fold), and WIF1 (difference, 12.17-fold) in the proximal colon and Wnt8b (difference, 16.95-fold) in the distal colon. Data are expressed as means ± SEM. Scale bar = 50 μm (A).