Laboratory of Molecular Immunology, The National Heart, Lung and Blood Institute, National Institutes of Health, Building 10, Room 7B05, 9,000 Rockville Pike, Bethesda, Maryland 20892, USA. schonesde@nhlbi.nih.gov
Over two metres of DNA is packaged into each nucleus in the human body in a manner that still allows for gene regulation. This remarkable feat is accomplished by the wrapping of DNA around histone proteins in repeating units of nucleosomes to form a structure known as chromatin. This chromatin structure is subject to various modifications that have profound influences on gene expression. Recently developed techniques to study chromatin modifications at a genome-wide scale are now allowing researchers to probe the complex components that make up epigenomes. Here we review genome-wide approaches to studying epigenomic structure and the exciting findings that have been obtained using these technologies.