The concept of epigenetics refers nowadays to the long-lasting and
inheritable gene expression states that are established in the absence of a change in the
DNA sequence itself. The fast progress of the field in later times has provided scientists
with novel understanding on how the environment in the wide sense, including
nutrition, exercise, even behavior of the organisms, participates in the regulation of gene
expression. The molecular mechanisms that mediate epigenetic regulation are
principally DNA methylation, the post-translational modifications of the histones and
the regulation by non-coding RNAs. They are intimately related to cell differentiation
and developmental plasticity and relay environmental influences to the cell nucleus,
thus bridging the gap between lifestyle and the genome. In this introductory chapter we
offer a general vision of the well-documented effects of lifestyle choices and
environmental impact on gene expression and present the reader with a general
overview of the better known epigenetic mechanisms and the techniques most often
used to study them.
Keywords: Chromatin, DNA methylation, histones, lifestyle.
