Epigenetics

C. H. Waddington (1942) was the first to describe epigenetics, when genetics was still flourishing. Waddington referred to epigenetics as an amalgam between genetics and epigenesis, he related epigenetics very much to embryonic development, and put forward the idea that the epigenetics is not entirely due to the “program ” encoded in DNA, but depends on environmental influences (Feinberg , A.P. 2007 ). His definition of epigenetics is extremely modern: “the causal interactions between genes and their products, which bring the phenotype into being ” , that echoes a contemporary definition: “ the inheritance of DNA activity that does not depend on the naked DNA sequence ” (Esteller , M. 2009 ) .

Literally the prefix epi means “over or above”. So, epigenetics is the science of “control above genetics”. It refers to a variety of processes that affect gene expression independent of actual DNA sequence. Epigenetic information provides instruction on how, where, and when, genetic information will be used. Hence, the importance of epigenetic information is that it regulates gene expression.

Epigenetics can refer to heritable effects on gene expression, or to the stable long-term alteration of the transcriptional potential of a cell, which may not necessarily be heritable. Most importantly, epigenetic information is susceptible to change, and as such, represents an excellent target to understand how the environment may impact physiological function. The impact could be manifest as long as the environmental factor is present or could persist, in its absence. The effect could be transient (during the duration) or extended (subsequent) to the environmental impact and although not necessarily transmittable (mitotically and/or meiotically) could exert significant influence (Mathews H. L. and Janusek L.W. 2011).

While genetic information provides the blueprint for the manufacture of the proteins necessary to cellular function; epigenetic information provides instruction for the use of that blueprint, permitting an ordered and regulated gene expression pattern.