An emerging field in neurobiology, the study of epigenetics is concerned with changes in the expression of the phenotype that are not a result of changes in the DNA sequence, but of external environmental and social factors that cause alterations in gene regulation. Undoubtedly, epigenetic study could be crucial in determining causation for dispositions that appear to have no genetic basis and research has already uncovered links between pre-natal care and post-birth conditions of babies.
The prefix Epi is from the Greek meaning “above”; epigenetics deals with change occurring within organisms beyond changes in the main DNA sequence. Thereby, changes to DNA and its associated proteins and modifications to histones in chromatin induce changes in the regulation of gene expression.
Society considers science to be the rhetoric of logic; being able to understand the world around us is after all, rooted in the ability to explain external and internal phenomena on a molecular as well as global and ecological scale. Despite the characteristically concrete nature of science, there are still multiple shades of grey within which concepts such as the epigenome are explored.
A classic example of epigenetics in action is the variation between identical twins. Although both twins have exactly the same genome, environmental and sociological factors influence their outward expression and contribution within their lives. It is important to note that such influential factors do not alter the genetic expression, but the phenotypic expression, and a fundamental concern of epigenetics is to source where such changes occur within organisms.
In a lifetime, the probability of meeting twins is fairly high, but other facets of epigenetics are manifested on a more discrete basis. Take an example of a recent experiment pioneered by a postdoctoral fellow in Kerry Ressler’s lab at Emory University that showed that mice from two generations down the line actually inherited the memories of their grandparents, giving them a survival advantage. Said grandparent mice were subjected to electric shocks, and the fear derived from this was inherited by mice two generations later, again exemplifying an alteration in phenotypic expression not as a result of genetic variation and adaptation, but of transgenerational epigenetic inheritance of behavioural traits.
With any fairly new development comes an element of doubt and contention and arguably, the concept of epigenetics is fairly new and cannot easily be digested without considering cases on an individual basis.
Nonetheless, the field provides yet more explanation for that which we previously had no grasp on, and thus is the dynamic nature of science as we know it.