In the early, online edition of Genome Research this week, MD Anderson Cancer Center researcher Jean-Pierre Issa and his team found DNA methylation levels shifts at some genes in aging mouse tissues. When they compared DNA methylation profiles at more than 3,600 genes in intestinal tissue from three-month-old and 35-month-old mice, the researchers found 774 genes with more methylation in the older mice and 466 with less methylation.