Of Mice and Methylation

Eric Lander's group has a new paper in the advance online section of Nature in which they describe how they used high-throughput reduced representation bisulphite sequencing coupled with single-molecule-based sequencing to generate DNA methylation maps from mouse primary tissues, including embryonic stem cells, embryonic-stem-cell-derived, and primary neural cells. They found that methylation patterns correlate with histone methylation patterns rather than with the genome sequence. They also say that CpG methylation is dynamic and that weak CpG islands associated with certain development genes undergo hypermethylation in vitro in a pattern they say is similar to what occurs in tumors.