Epigenetics refers to a set of reversible heritable changes in gene expression or function due to mechanisms other than changes in the underlying DNA sequence.

Epigenetics is a relatively new research field. The molecular basis of epigenetics is complex; put simply it refers to altered DNA structure. It involves modifications of the activation of certain genes, but not the basic DNA sequence.

These modifications, affect the expression of a gene, but not the primary DNA sequence itself.

For example, DNA methylation refers to the addition of methyl groups to the DNA, which in turn affects transcriptional activity.

Folate status can affect DNA methylation, which in turn can affect gene expression through mechanisms that are being actively researched. Epigenetic processes include, among others, imprinting, gene silencing, X chromosome inactivation, and gene regulation by histone modification. In summary, epigenetics deals with modification of genes that determines whether a gene is expressed or not.

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    Adapted from Thompson & Thompson Genetics in Medicine E-Book By Robert L. Nussbaum, Roderick R. McInnes, Huntington F Willard