Originally published Feb 14, 2017 and updated Jun 24, 2020.
Epigenetic modifications are an additional layer of control over gene expression that go beyond genomic sequence. Dysregulation of the epigenome (the sum of epigenetic modifications across the genome) has been implicated in disease states, and targeting the epigenome may make certain processes, like cellular reprogramming of iPSCs, more efficient. In general, epigenetic chromatin modifications are correlated with alterations in gene expression, but causality and mechanisms remain unclear. Today, targeted epigenetic modification at specific genomic loci is possible using CRISPR, and Addgene has a number of tools for this purpose.