Epigenomics Defined

Epigenetics is the study of gene expression and regulation within a species, independent of the genetic sequence. Epigenomics, by complement, looks at expression and regulation across the entire genome, not just individual genes or sets of genes like epigenetics. Just because an individual has a mutation free form of a gene does not mean the individual is disease free. The abundance of protein produced by the gene may be too great or not enough; possibly causing a disease state in either or both instances. The amount of protein produced from a gene is known as gene expression. Overexpression and one has an over abundance of the protein. Underexpression and the cell will not produce a sufficient amount of the protein. In a typical cell there are variety of mechanisms and processes that play a role in gene expression and regulation, include DNA methylation and numerous environmental factors.

An interesting study from Duke University looked at the impact of Bisphenol A (BPA) in agouti mice. BPA has been found to be present in many types of plastics used for food containers, bottles and dental sealants and has been found to affect the offspring of the mothers who ingest it. The study discovered the progeny of genetically identical twin mice that had ingested BPA looked different; they had lighter colored coats and were larger, even obese. And more so depending on the amount of BPA ingested by the mother, such that you could almost chart the amount of BPA in their system just by looking at their coat color and size. These mice were also found to be more susceptible to diabetes and cancer. It has been found that BPA affects the DNA methylation of the agouti gene, which directly contributes to its expression and the amount of the agouti protein produced. An unmethylated agouti gene creates an overabundance of the protein causing the disease state.

The remarkable part of the study was when they fed the infected mice soy product; known to contain the methyl group utilized in DNA methylation of the agouti gene. The results of the soy diet were astonishing. The infected mice progeny showed signs of reversal as their coats were darker and their size slimer; to a more healthy level. The final results showed that a maternal diet rich in soy almost completed reversed the effects of BPA poisoning in offspring.

As the fields of genetics, genomics and proteomics mature it has become increasingly clear that gene expression and regulation play a huge role in disease states caused by an overabundance or lack of sufficient protein concentration. Epigenetics studies the various mechanisms, processes and environmental factors involved in gene expression. In the case of the Duke University mice study, Epigenetics proved invaluable a reversing the ill effects of BPA poisoning with a simple maternal dietary modification.

Chaddha R. A Tale of Two Mice [Internet]. PBS. PBS; 2007 [cited 2016Nov23]. Available from: http://www.pbs.org/wgbh/nova/body/epigenetic-mice.html

NIH Common Fund Epigenomics [Internet]. U.S National Library of Medicine. U.S. National Library of Medicine; [cited 2016Nov23]. Available from: https://commonfund.nih.gov/epigenomics/