Sensing the Environment: Epigenetic Regulation of Gene Expression

Abstract

The genomic era has just scratched the surface of the complex mechanisms responsible for bringing the organism phenotype into their being. In light of the recent discoveries, it is becoming clear that “other genetic” and environmental factors tightly interplay to provide information and instructions for the use of genetic material. Under this point of view, the DNA represents “the hardware”, the first ancestral genetic layer of cell information that is identical in all tissues of the individual; another layer of information differently distributed across the genome, continuously written, read and erased in response to both physical and social environmental signals, represents the cell “software”, the network connection with the changing world around us. Conrad H. Waddington (1942) termed this concept epigenetics to describe the hypothetical interaction among genes and their immediate surroundings during development and phenotype determination. Epigenetics is referred as the ensemble of functionally relevant modifications that regulate gene expression without altering the underlying DNA sequence. This article will examine the interaction between the genome, epigenome and environment with reference to how and when external signals affect long-term regulation of transcriptional programs.