A longitudinal study of epigenetic variation in twins.


DNA methylation is a key epigenetic mechanism involved in the developmental regulation of gene expression. Alterations in DNA methylation are established contributors to inter-individual phenotypic variation and have been associated with disease susceptibility. The degree to which changes in loci-specific DNA methylation are under the influence of heritable and environmental factors is largely unknown. In this study, we quantitatively measured DNA methylation across the promoter regions of the dopamine receptor 4 gene (DRD4), the serotonin transporter gene (SLC6A4/SERT) and the X-linked monoamine oxidase A gene (MAOA) using DNA sampled at both ages 5 and 10 years in 46 MZ twin-pairs and 45 DZ twin-pairs (total n=182). Our data suggest that DNA methylation differences are apparent already in early childhood, even between genetically identical individuals, and that individual differences in methylation are not stable over time. Our longitudinal-developmental study suggests that environmental influences are important factors accounting for interindividual DNA methylation differences, and that these influences differ across the genome. The observation of dynamic changes in DNA methylation over time highlights the importance of longitudinal research designs for epigenetic research.







Avshalom Caspi

Edward M. Arnett Distinguished Professor of Psychology and Neuroscience

Caspi’s research is concerned with three questions: (1) How do childhood experiences shape aging and the course of health inequalities across the life span?  (2) How do genetic differences between people shape the way they respond to their environments? (3) How do mental health problems unfold across and shape the life course? 


Terrie E. Moffitt

Nannerl O. Keohane University Distinguished Professor

Terrie E. Moffitt, Ph.D., is the Nannerl O. Keohane University Professor of Psychology at Duke University, and Professor of Social Development at King’s College London. Her expertise is in the areas of longitudinal methods, developmental theory, mental disorders and antisocial behaviors, neuropsychology, and genomics in behavioral science. She is currently uncovering the consequences of a lifetime of mental and behavioral disorder on processes of aging. She is the Associate Director of the Dunedin Longitudinal Study, which follows a 1972 birth cohort in New Zealand. She also co-founded the Environmental Risk Longitudinal Twin Study (E-Risk), which follows a 1994 birth cohort in the UK. Dr. Moffitt also is a licensed clinical psychologist, with specialization in neuropsychological assessment. She collaborates with criminologists, economists, geneticists, epidemiologists, sociologists, demographers, gerontologists, statisticians, neuroscientists, medical scientists, opthalmologists, and dentists. Dr. Moffitt is a fellow of the National Academy of Medicine and  the American Academy of Arts and Sciences , as well as the British Academy, Academy of Medical Sciences (UK), Academia Europa, Association of Psychological Science, and the American Society of Criminology. She holds honorary doctorates from the Katholieke Universiteit Leuven, Belgium, and Universitat Basel, Switzerland. For her research, Dr. Moffitt has received both the American Psychological Association's Early Career Contribution Award and Distinguished Career Award. Dr. Moffitt was also awarded a Royal Society-Wolfson Merit Award, the Klaus-Grawe Prize, and was a recipient of the Stockholm Prize in Criminology, NARSAD Ruane Prize, the Klaus J. Jacobs Research Prize, and in 2022 the Grawemeyer Prize. Her service includes serving as chair of the Board on Behavioral, Cognitive, and Sensory Science at NASEM, Chair of the NIA Data Monitoring Committee for the Health and Retirement Study, and Chair of the Jury for the Klaus J. Jacobs Prize in Switzerland. Dr. Moffitt attended the University of North Carolina at Chapel Hill for her undergraduate degree in psychology. She continued her training in psychology at the University of Southern California, receiving an M.A. in experimental animal behavior, and a Ph.D. in clinical psychology. She also completed postdoctoral training in geriatrics and neuropsychology at the University of California Los Angeles Neuropsychiatric Institute. In her spare time, she works on her poison-ivy farm in North Carolina.

Unless otherwise indicated, scholarly articles published by Duke faculty members are made available here with a CC-BY-NC (Creative Commons Attribution Non-Commercial) license, as enabled by the Duke Open Access Policy. If you wish to use the materials in ways not already permitted under CC-BY-NC, please consult the copyright owner. Other materials are made available here through the author’s grant of a non-exclusive license to make their work openly accessible.