Haque F Nipa, Gottesman Irving I, Wong Albert H C
University of Toronto, Toronto, Ontario, Canada.
Am J Med Genet C Semin Med Genet. 2009 May 15;151C(2):136-41. doi: 10.1002/ajmg.c.30206.
Classical twin studies in the field of psychiatry generally fall into one of two categories: (1) those designed to identify environmental risk factors causing discordance in monozygotic (MZ) twins and (2) those geared towards identifying genetic risk factors. However, neither environment nor differences in DNA sequence can fully account for phenotypic discordance among MZ twins. The field of epigenetics--DNA modifications that can affect gene expression--offers new models to understand discordance in MZ twins. In the past, MZ twins were regarded as genetically-identical controls for differing environmental conditions. In contrast, the evolving current concept is that epigenetic differences between MZ twins may modulate differences in diverse phenotype, from disease to personality. In this article, we review some twin studies, and discuss the dynamic interactions between stochastic, environmental, and epigenetic variables that influence neurobiological phenotypes.
（1）旨在识别导致同卵双胞胎出现不一致情况的环境风险因素的研究，以及（2）旨在识别遗传风险因素的研究。然而，环境和DNA序列差异都不能完全解释同卵双胞胎之间的表型不一致。表观遗传学领域——能够影响基因表达的DNA修饰——为理解同卵双胞胎的不一致提供了新的模型。过去，同卵双胞胎被视为不同环境条件下的基因相同的对照。相比之下，当前不断发展的概念是，同卵双胞胎之间的表观遗传差异可能会调节从疾病到个性等各种表型的差异。在本文中，我们回顾了一些双胞胎研究，并讨论了影响神经生物学表型的随机、环境和表观遗传变量之间的动态相互作用。
