Epigenomics

epigenomics, the study of chemical changes that regulate the expression, or use, of the entire collection of DNA molecules in an organism’s cells. This collection of genetic material is known as the organism’s genome. Genomes serve as dynamic blueprints, directly or indirectly enabling the synthesis of all the macromolecules needed for life. Epigenomics is the study of the regulated expression of those blueprints. More precisely, it is the study of how, when, where, and why cells decorate specific regions of their DNA in sometimes heritable and sometimes temporary ways in order to activate or silence the expression of specific genes. These modifications of DNA, known as epigenetic changes, enable healthy cells to respond to environmental changes and to differentiate during development. Epigenetic modifications also enable species to silence parasitic DNA elements, such as transposons or retroviruses, that long ago invaded and now exist as permanent interlopers in their genomes. Sometimes, however, aberrant epigenetic changes can lead to inherited or acquired disorders.