The definition of epigenetics is still under intense debate; however, its concept has evolved since it was originally introduced in 1939 by Conrad Hal Waddington as a way to reconcile antagonistic views between the school of preformationism and the school of epigenesis. The characterization of a large number of phenomena that diverge from the dogmas of classical genetics, and the discovery of the molecular mechanisms through which these phenomena occur, has given rise to a new area of study with important implications for biological sciences. Interactions between the environment and the DNA through modifications on the chromatin are not only responsible for the expression of a normal phenotype, these may be involved in the development of various pathologies. The epigenome, as the bridge between the genome and the phenotype, is no doubt one of the most interesting current ideas in genetics and is so revolutionary that it may change our present notions about inheritance and evolution. In this review, we made a compilation of the most important events in the history of epigenetics, its implications and some perspectives to the future.

Abbreviations: DNA: deoxyribonucleic acid; RNA: ribonucleic acid; DNMT: DNA methyltransferase; MBP: methyl-CpG-binding proteins; HAT: histone acetyltransferase; HDAC: histone deacetylase; SAM: S-adenosyl methionine; ncRNA: non-coding RNA; rRNA: ribosomal RNA; miRNA: microRNA; siRNA: small interfering RNA; piRNA: Piwi-interacting RNA; XiRNA: X-inactivation RNA; lncRNA: long non-coding RNA; GR: glucocorticoid receptor; IGF2: insulin-like growth factor II; HPA: hypothalamic–pituitary–adrenal; TSA: trichostatin A; LINE: long interspersed nuclear elements; LOI: loss of genomic imprinting; MAS: McCune–Albright syndrome; AS: Angelman syndrome; PWS: Prader–Willi syndrome; FDA: Food and Drug Administration; AHEAD: International Human Epigenome Project; HEP: Human Epigenome Project; TMG: thiomethyl-β-D-galactoside

表观遗传学的定义仍在激烈辩论中。但是，它的概念自1939年由康拉德·哈尔·沃丁顿（Conrad Hal Waddington）最初提出以来就得到了发展，该方法是调和预制主义派和表观遗传派之间的对立观点的一种方式。大量与经典遗传学教义不同的现象的表征，以及这些现象发生的分子机制的发现，引起了一个新的研究领域，对生物学产生了重要的影响。通过染色质修饰，环境与DNA之间的相互作用不仅负责正常表型的表达，而且还可能参与了各种病理学的发展。表观基因组，作为基因组和表型之间的桥梁，毫无疑问，它是当前遗传学中最有趣的思想之一，并且具有革命性，以至于可以改变我们目前关于遗传和进化的观念。在这篇综述中，我们汇总了表观遗传学历史上最重要的事件，其影响以及对未来的一些看法。

缩写： DNA：脱氧核糖核酸；RNA：核糖核酸；DNMT：DNA甲基转移酶；MBP：甲基-CpG结合蛋白；HAT：组蛋白乙酰转移酶；HDAC：组蛋白脱乙酰基酶；SAM：S-腺苷甲硫氨酸；ncRNA：非编码RNA；rRNA：核糖体RNA；miRNA：microRNA；siRNA：小干扰RNA；piRNA：Piwi相互作用RNA；XiRNA：X灭活RNA；lncRNA：长的非编码RNA；GR：糖皮质激素受体；IGF2：胰岛素样生长因子II；HPA：下丘脑-垂体-肾上腺；TSA：曲古抑菌素A；线：散布着长核的元素；意向书：基因组印记的丧失；MAS：McCune–Albright综合征；AS：安格曼综合症；PWS：普拉德-威利综合症；FDA：食品药品管理局；提前：国际人类表观基因组计划；HEP：人类表观基因组计划；TMG：硫甲基-β-D-半乳糖苷