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Not really identical: Epigenetic differences in monozygotic twins and implications for twin studies in psychiatry
Author(s) -
Haque F. Nipa,
Gottesman Irving I.,
Wong Albert H.C.
Publication year - 2009
Publication title -
american journal of medical genetics part c: seminars in medical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.419
H-Index - 101
eISSN - 1552-4876
pISSN - 1552-4868
DOI - 10.1002/ajmg.c.30206
Subject(s) - epigenetics , twin study , monozygotic twin , phenotype , genetics , biology , dna methylation , affect (linguistics) , psychology , identical twins , developmental psychology , evolutionary biology , gene , gene expression , heritability , communication
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. © 2009 Wiley‐Liss, Inc.