Epigenetic variation.

Epigenetics is a fast moving field and our understanding of epigenetic mechanisms has dramatically improved in recent decades. We present the role that epigenetics plays in genomic control in humans; the molecular basis of this control and the role that epigenetic aberrations play in the aetiology of human disease. We outline some of the laboratory techniques for characterising epigenetic variation from methylation analysis of a single CpG to characterising histone variation across extensive genomic regions. The fields of computational epigenetics and population epigenetics have recently emerged and we discuss developments in statistical methods that use DNA methylation as biomarker for the prediction of disease. Finally we describe how DNA methylation errors that occur during somatic cell divisions have been used as a molecular clock that allows inferences about cell population histories to be made.