What makes up the epigenome?

The epigenome is made up of chemical compounds and proteins that can bind to DNA, influencing gene activity within cells by either activating or repressing gene expression. Thus, these modifications regulate the production of proteins in specific cells by controlling the accessibility of genes to cellular processes. When these epigenetic compounds bind to DNA and alter its function, they "mark" the genome, meaning that they have modified its activity without changing the underlying DNA sequence. These marks vary between different cell types. Although not part of the DNA sequence, they can be inherited from parent cells during cell division and passed on to subsequent generations.