About Epigenetic modification
Epigenetics is the study of cellular and physiological variations which are not caused by changes in the DNA sequence. Epigenetics is essentially the study of external or environmental factors that turn genes on and off and affect how cells read genes. Hence epigenetic research seeks to describe dynamic alterations in the transcriptional potential of a cell. At least three systems including DNA methylation, histone modification and non-coding RNA (ncRNA)-associated gene silencing are currently considered to initiate and sustain epigenetic change.