DNA methylation profiling of colonic mucosal DNA between P90 and P30 mice. 0.5ug of DNA was serially digested with SmaI and XmaI followed by an adaptor ligation and adaptor mediated PCR amplification Two independent P90 to P30 comparisons were performed as follows. Samples were labelled with Cy3 (P30) and Cy5 (P90) and two independent P90 to P30 comparisons were done on a 2x105k methylation specific amplification microarray (MSAM) containing 90,535 probes, covering 77% of the 31,019 SmaI intervals between 200 bp and 2 kb in the mouse genome (average 3.8 probes per interval)