title: Transgenerational epigenetic inheritance in mammals: how good is the evidence?
abstract: Epigenetics plays an important role in orchestrating key biologic processes. Epigenetic marks, including DNA methylation, histones, chromatin structure, and noncoding RNAs, are modified throughout life in response to environmental and behavioral influences. With each new generation, DNA methylation patterns are erased in gametes and reset after fertilization, probably to prevent these epigenetic marks from being transferred from parents to their offspring. However, some recent animal studies suggest an apparent resistance to complete erasure of epigenetic marks during early development, enabling transgenerational epigenetic inheritance. Whether there are similar mechanisms in humans remains unclear, with the exception of epigenetic imprinting. Nevertheless, a distinctly different mechanism-namely, intrauterine exposure to environmental stressors that may affect establishment of the newly composing epigenetic patterns after fertilization-is often confused with transgenerational epigenetic inheritance. In this review, we delineate the definition of and requirement for transgenerational epigenetic inheritance, differentiate it from the consequences of intrauterine exposure, and discuss the available evidence in both animal models and humans.-Van Otterdijk, S. D., Michels, K. B. Transgenerational epigenetic inheritance in mammals: how good is the evidence?
authors.affiliation: Institute for Prevention and Cancer Epidemiology, University Medical Center Freiburg, Freiburg, Germany;
authors.forename: Sanne D
authors.initials: SD
authors.lastname: van Otterdijk
authors.affiliation: Institute for Prevention and Cancer Epidemiology, University Medical Center Freiburg, Freiburg, Germany; Obstetrics and Gynecology Epidemiology Center, Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts kmichels@bwh.harvard.edu.
authors.forename: Karin B
authors.initials: KB
authors.lastname: Michels
mesh_terms: D000818:Animals; D019175:DNA Methylation; D044127:Epigenesis, Genetic / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D040582:Inheritance Patterns; D008322:Mammals / Q000235:genetics*
keywords: DNA methylation; IAP elements; imprinting; intrauterine exposure; reprogramming