How does epigenetics work?

The primary mechanisms through which epigenetics functions is via DNA methylation, histone modification, and non-coding RNA regulation. 

DNA methylation involves adding a chemical group to specific places on the DNA, which prevents the proteins that read the genes from accessing them. This addition of a chemical group can be reversed in a process called demethylation. Methylation typically turns genes off, while demethylation turns genes on. 

Non-coding RNA plays a role in controlling gene expression. It can interact with coding RNA to degrade it, preventing the production of proteins. Additionally, non-coding RNA can recruit proteins to modify histones. 

For the process of histone modification, when histones are tightly packed together, the DNA is less accessible to the proteins that read the genes and leads to gene suppression. When histones are loosely packed, more DNA is exposed, allowing the genes to be read and expressed. Chemical groups can be added or removed from histones to regulate how tightly or loosely they pack the DNA.