title: Epigenetics of personality traits: an illustrative study of identical twins discordant for risk-taking behavior.
abstract: DNA methylation differences between identical twins could account for phenotypic twin discordance of behavioral traits and diseases. High throughput epigenomic microarray profiling can be a strategy of choice for identification of epigenetic differences in phenotypically different monozygotic (MZ) twins. Epigenomic profiling of a pair of MZ twins with quantified measures of psychometric discordance identified several DNA methylation differences, some of which may have developmental and behavioral implications and are consistent with the contrasting psychometric profiles of the twins. In particular, differential methylation of CpG islands proximal to the homeobox DLX1 gene could modulate stress responses and risk taking behavior, and deserve further attention as a potential marker of aversion to danger. The epigenetic difference detected at DLX1 of approximately 1.2 fold change was used to evaluate experimental design issues such as the required numbers of technical replicates. It also enabled us to estimate the power this technique would have to detect a functionally relevant epigenetic difference given a range of 1 to 50 twin pairs. We found that use of epigenomic microarray profiling in a relatively small number (15-25) of phenotypically discordant twin pairs has sufficient power to detect 1.2 fold epigenetic changes.
authors.affiliation: The Krembil Family Epigenetics Laboratory, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Kaminsky
authors.forename: Arturas
authors.initials: A
authors.lastname: Petronis
authors.forename: Sun-Chong
authors.initials: SC
authors.lastname: Wang
authors.forename: Brian
authors.initials: B
authors.lastname: Levine
authors.forename: Omar
authors.initials: O
authors.lastname: Ghaffar
authors.forename: Darlene
authors.initials: D
authors.lastname: Floden
authors.forename: Anthony
authors.initials: A
authors.lastname: Feinstein
mesh_terms: D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005260:Female; D006801:Humans; D008875:Middle Aged; D040081:Protein Array Analysis; D011594:Psychometrics; D019655:Quantitative Trait, Heritable; D012309:Risk-Taking; D014430:Twins, Monozygotic