Epigenetics

What is Epigenetics?

The American Association for the Advancement of Science defines epigenetics as the study of nongenetic cellular memory that records developmental, environmental cues, and alternate cell states in unicellular organisms. The lack of identified genetic determinants that fully explain the heritability of complex traits, and the inability to pinpoint causative genetic effects in some complex diseases, suggest possible explanations relating to epigenetics for the missing information. 

Live Science also states epigenetics as the turning "on" and "on top of" genetics. It refers to the external modifications to DNA that affect how cells "read" genes and they alter the physical structure of DNA. One example of a change involving epigenetics is DNA methylation, which is the addition of a methyl group, or a "chemical cap", to the part of the DNA molecule, which prevents genes from being expressed. 

How has Epigenetics Changed Our Current Understanding of Genetics?

Science Daily reports that, Increasingly, biologists are finding that non-genetic variation acquired during the life of an organism can sometimes be passed on to offspring - a phenomenon known as epigenetic inheritance. An article forthcoming in the July issue of The Quarterly Review of Biology lists over 100 well-documented cases of epigenetic inheritance between generations of organisms, and suggests that non-DNA inheritance happens much more often than scientists previously thought. Biologists have suspected for years that some kind of epigenetic inheritance occurs at the cellular level. The different kinds of cells in our bodies provide an example. Skin cells and brain cells have different forms and functions, despite having exactly the same DNA. There must be mechanisms—other than DNA—that make sure skin cells stay skin cells when they divide. Only recently, however, have researchers begun to find molecular evidence of non-DNA inheritance between organisms as well as between cells.

Why Does Epigenetics Matter?

Epigenetics is important in the understanding of how lifestyle and behavioral aspects impact cell states in organisms. This impacts our understanding of genetics tremendously with the noted factors that can alter DNA of the cell and tells us what types of external impacts can impact future generations. Let's Get Healthy states, "Previously, we thought that the way that our DNA and genes acted was determined by what we got from our parents. Genes are sections of DNA that perform a certain function and we get two copies of each gene – one from mom, one from dad. Epigenetics research has shown that some CHOICES that we make can impact how our genes behave. This happens because some actions can produce or change the epigenetic markings on DNA that can turn the activity of certain genes up or down.”

How Old is the Science?

John Hopkins Medicine shares that in the early 1940s, Dr. Waddington, an embryologist, put forth a radical idea for its era. Most embryologists did not believe genes were important in human development; rather, they contended that genes played a minor role, controlling inconsequential details like eye color. Dr. Waddington disagreed and introduced the concept of genes and their regulation via an epigenetic landscape, as controlling cell fate and how cells become specialized. The epigenetic landscape that Dr. Waddington first referred to more than a half century ago is just now beginning to be understood, particularly how it applies to cancer. Epigenetics is a fairly new discovery in the understanding of alteration of cell states in unicellular organisms and has had a major impact in the field of genetics.