The document discusses epigenetics, which is the study of changes in gene expression that are not caused by changes in DNA sequence. An epigenome consists of molecular "switches" that turn genes on and off in response to environmental factors like diet, stress, and lifestyle choices. Experiments have found links between early life experiences like famine or smoking and health outcomes in later generations through epigenetic mechanisms. Scientists are researching epigenetics to develop new drugs that can manipulate epigenomes to treat diseases.