DNA methylation and epigenetics.

In many eukaryotes, including plants, DNA methylation provides a heritable mark that guides formation of transcriptionally silent heterochromatin. In plants, aberrant RNA signals direct DNA methylation to target sequences, sometimes appropriately and sometimes inappropriately. This chapter discusses the generation of RNA signals for epigenetic changes, the factors that mediate those changes, and some of the consequences of those changes for plant gene expression and genome integrity.