Plant Epigenomics

Epigenetic regulation is highly conserved in eukaryotes. In general, events mediated by the genome - such as the regulation of gene activity and establishment and arrangement of chromatin structure - are coordinated by epigenetic and chromatin-remodeling factors. The concept of epigenetics was coined by Waddington (1957). In the context of embryogenesis, cells are affected by particular circumstances during development. This idea involves the possibility of "epi" factors that determine cell fate ("epi" is a Greek prefix meaning "external action or effect"). Currently, the definition of epigenetics remains interpretive in various contexts; however, the concept is based on "heritable phenotype changes that do not involve alterations in DNA sequence" and involves "nonheritable chromatin-level regulation that does not involve alterations in DNA sequence." In this chapter, the basic concepts of genome-wide regulation of histone modifications and DNA methylation - known as epigenetic and chromatin regulatory factors - are the primary focus, with an emphasis on understanding the fundamental mechanisms of epigenetic regulation.