Previous studies using the IL-10-/- model of colitis have either used denaturing gradient gel electrophoresis (DGGE) for their analysis of microbial compositional (40, 42) or have only collected fecal pellets for 4 weeks post-colonization of germ-free mice with a SPF microbiota or at 8 and 10 weeks of age (39). This evidence concerns the gene IL10 and colitis.