The First High-Resolution DNA “Methylome”

Cytosine methylation plays a crucial role in the regulation of gene expression and the control of genome stability in higher eukaryotes. Despite its importance for normal development, the degree and genome-wide distribution of DNA methylation has remained largely unknown. In this issue of Cell, Zhang et al. (2006) fill this gap by presenting a high-resolution map of DNA methylation in the genome of the flowering plant Arabidopsis.